Showing papers in "Aquaculture Nutrition in 1999"
TL;DR: A commonly used equation for the calculation of the apparent digestibility coefficients of feedstuffs for fish and crustaceans is shown to be incorrect and the correct (but rarely used) equation is presented and contrasted with the previous equation.
Abstract: A commonly used equation for the calculation of the apparent digestibility coefficients of feedstuffs for fish and crustaceans is shown to be incorrect. The correct (but rarely used) equation is presented and contrasted with the previous equation. Data from a previously published trial is used to illustrate the differences between these equations. In many cases, the values obtained using the two equations is very similar. Larger differences are found, however, when the level and digestibility of the nutrient in the test ingredient are greatly different from those in the reference diet.
187 citations
TL;DR: In fish of similar weight there was a positive correlation between dietary lipid and muscle lipid concentrations, and all values were within normal ranges for Atlantic salmon of these sizes.
Abstract: This study was conducted to determine the effects of feeding increasing lipid concentrations (310, 380 and 470 g kg(-1) lipid on dry weight) in diets based mainly on herring byproducts to Atlantic salmon Salmo salar. The diets were isonitrogenous, varying in dietary lipid content at the expense dietary starch. Average fish weight increased from 1.2 kg in April to 2.2-2.7 kg at the end of the feeding trial in September. Significantly greater growth was found in fish fed either the 380 g kg(-1) or the 470 g kg(-1) lipid diets compared with the 310 g kg(-1) lipid diet. Muscle lipid content increased in all dietary groups on a wet weight basis from 7.7 +/- 1.4% to 12 +/- 3% in salmon fed the 310 g kg(-1) lipid diet, and to 16 +/- 2% in salmon fed the 380 g kg(-1) and 470 g kg(-1) lipid diets. In fish of similar weight there was a positive correlation between dietary lipid and muscle lipid concentrations. Low concentrations of muscle glycogen were detected in fish fed each of the diets, while muscle vitamin E concentrations slowly decreased as muscle lipid increased. Muscle fatty acid composition reflected dietary fatty acid profiles, containing similar percentages of total saturated, monoenic and n-3 fatty acids (20:5n-3 and 22:6n-3) in fish from all dietary treatment groups. However, a higher ratio of n-3/n-6 was found in muscle from fish fed the 470 g kg(-1) lipid diet compared with the other two groups. Blood chemistry values varied somewhat, but all values were within normal ranges for Atlantic salmon of these sizes.
182 citations
TL;DR: In this paper, the relative importance of nutrient composition and levels of antinutritional factors present in various canola protein products derived from the processing of commercial canola meal (CCM) on digestibility in rainbow trout held in 9.9-11°C fresh water.
Abstract: This study was undertaken to assess the relative importance of nutrient composition and levels of antinutritional factors present in various canola protein products derived from the processing of commercial canola meal (CCM) on digestibility in rainbow trout held in 9.9–11°C fresh water.
Laboratory sieving of CCM (SCM) reduced levels of crude fibre, cellulose and hemicellulose by 31.6%, 16.6% and 56.4%, respectively. Aqueous methanol–ammonia washing of sieved canola meal (ACM) increased neutral detergent fibre (NDF, insoluble dietary fibre) and phytate, and dramatically decreased levels of total glucosinolates (> 88%) and phenolic compounds (≈ 59%) relative to CCM. Further treatment of ACM with phytase in acidified (pH 5.0) aqueous media (PCM), followed by filtration, increased levels of crude protein, crude fibre and NDF, and decreased levels of phytate (33%), phenolic compounds (81%) and glucosinolates (below detection limit) relative to CCM. Additional treatment of PCM with carbohydrase enzymes (SP-249 and/or Alpha Gal, an oligosaccharide-degrading enzyme) further elevated levels of NDF, cellulose, protein (SP-249 only) and indispensable amino acids (SP-249/Alpha Gal), and concurrently decreased levels of phytate relative to PCM. An industrial source of canola protein isolate (CPI), produced by first extracting CCM with aqueous salt solution and then recovering the protein fraction, had the best nutrient composition and lowest levels of the antinutritional factors mentioned above. The processing protocols had slight or marked negative effects (ACM and SP-249/Alpha Gal) on apparent dry matter digestibility. Protein digestibility coefficients were unaltered in the laboratory-processed products, except for the products treated with SP-249 and SP-249/Alpha-Gal. In these cases, the protein digestibility coefficients (77.4% and 79.5%) were significantly below that found for CCM (88.1%). With two of the treatments, ACM and SP-249/Alpha-Gal, processing depressed DE. In contrast, the DE level in CPI (20.6 MJ kg−1) and the digestibility coefficients for dry matter (77.1%) and protein (97.6%) were high.
We conclude that high levels of fibre, either alone or together with phytate, have the greatest adverse effects on the digestibility of canola protein products for rainbow trout. The high digestibility of CPI and its low content of antinutritional factors may also enable this protein product to be an excellent substitute for premium quality fish meal in diets for salmonids.
152 citations
TL;DR: Phosphorus load to the environment, measured as percentage retention of ingested or digestible phosphorus, was significantly lower with both diets higher in lipids, and nitrogen retention was significantly higher with high fat diets regardless of dietary protein level.
Abstract: Gilthead seabream Sparus aurata L. (initial mean body weight: 42.5 g) were fed four experimental diets containing either 47 or 51% of dry matter (DM) as protein and either 15 or 21% as lipid for 12 weeks. Each diet was hand-distributed to triplicate groups of 60 fish, three times a day until satiation. The digestibility coefficients of the dietary components were determined using chromic oxide as a marker. The levels of protein or lipid in the diets did not affect the digestibility. Fish regulated their feed intake and attained the same weight at the end of the experiment. However, feed efficiency varied between diets, with best values obtained with both diets containing 21% lipid. When diets contained only 15% lipid, feed efficiency increased with dietary protein level. Nitrogen retention was significantly higher with high fat diets regardless of dietary protein level. Neutral lipid deposition was significantly higher in liver for diets rich in lipids. It was elevated in muscle only in fish fed the diet containing 47% protein and 21% lipid and this deposition in muscle contributed to a significant increase in body fat content. Phosphorus load to the environment, measured as percentage retention of ingested or digestible phosphorus, was significantly lower with both diets higher in lipids.
142 citations
TL;DR: To regain efficient nutrient digestion after a fasting period, a restoration period may therefore be needed.
Abstract: Atlantic salmon (1.9 kg), were fed a low carbohydrate/high protein or a high carbohydrate/low protein diet for 20 days prior to a fasting period of 60 days. At the end of the feeding period chyme was collected from the gastro-intestinal tract divided into six sections, for studies of starch, lipid and amino acid absorption. Blood and gut wall samples were taken on days 0, 5, 12, 33 and 60 of fasting. The results showed that 50% or more of amino acid, lipid and starch absorption took place in the pyloric region. The distal intestine was also of quantitative importance for lipid absorption. Diet composition affected only starch absorption. The effect was apparent in the pyloric region with no compensatory absorption in the more distal regions. Brush-border disaccharidase activities were negligible in the stomach, high in mid-intestinal regions and decreased towards the distal regions. High carbohydrate diet caused reduced trehalase activity. Fasting caused immediate decreases in disaccharidase activities as well as in plasma glucose, triacylglycerols, cholesterol and insulin. During the second week of the fasting period, temporary increases were seen in mucosal maltase, sucrase and trehalase activities and in plasma insulin level. Similar changes were observed for several plasma amino acids. To regain efficient nutrient digestion after a fasting period, a restoration period may therefore be needed.
118 citations
TL;DR: A positive effect of phytase treatment, particularly on phosphorus digestibility and retention, and consequently the phosphorus conversion efficiency and the phosphorus budget is indicated.
Abstract: Balance trials were conducted with African catfish Clarias gariepinus to assess the effect of phytase treatment of soybean meal-based diets on growth, feed utilization and nutrient budgets. Isocaloric (20-22 kJ g(-1)) and isonitrogenous (47-50% protein) diets were tested. In a first experiment the control diet (58% fish meal and 18% soybean meal) was compared with two diets containing 6% fish meal and 69% soybean meal, and two diets containing 29% fish meal and 41% soybean meal. One of each of these two diets had been pretreated with phytase (1000 units per kg dry diet). In the second experiment, the control diet (6% fish meal and 69% soybean meal, pretreated with 1000 units phytase kg(-1) dry diet) was compared with four diets that were similar in composition but supplemented with increasing amounts of phytase(15, 380, 750, 1000 units kg(-1) dry diet). Replacement of fish meal by soybean meal in the first experiment led to a depression in growth rate and feed utilization parameters. Results of both experiments clearly indicated a positive effect of phytase treatment, particularly on phosphorus digestibility and retention, and consequently the phosphorus conversion efficiency and the phosphorus budget. No differences in these parameters were found between addition of equal amounts of phytase by pretreatment or supplementation.
110 citations
TL;DR: The dietary methionine requirement of juvenile Arctic charr Salvelinus alpinus was assessed by feeding diets supplemented with graded levels of DL-methionine for 16 weeks at 12°C and the prevalence of cataracts appears to be higher than that required for maximum growth.
Abstract: The dietary methionine requirement of juvenile Arctic charr Salvelinus alpinus (L.) was assessed by feeding diets supplemented with graded levels of DL-methionine (9, 12, 15, 18, 21, and 24 g kg−1dietary protein) for 16 weeks at 12°C. All diets contained 400 g kg−1 protein, 170 g kg−1 lipid, 66 g kg−1 ash and an estimated 17.5 MJ digestible energy (DE) kg−1. When live-weight gain was examined using quadratic regression, the estimate of methionine requirement for optimal growth was 17.6 g kg−1 of dietary protein (DP) or 7 g kg−1 of the diet. Requirements estimated on the basis of carcass protein and energy gains were 18.8 and 17.9 g kg−1 DP, respectively. Plasma methionine concentrations and ocular focal length variability measurements did not provide a sensitive measure of requirement, because each responded in a linear fashion to increasing dietary methionine levels. Based on the prevalence of cataracts, the methionine level required to prevent lens pathology (26.7 g kg−1 DP) appears to be higher than that required for maximum growth.
95 citations
TL;DR: The interaction between lysine source and feeding frequency was not significant, indicating that feeding frequency did not affect the utilization of free L-lysine relative to that of protein-bound l Lysine, and suggesting that free lysines would be absorbed before protein- bound lysined.
Abstract: Previous research has demonstrated that free lysine is utilized less efficiently for growth than protein-bound lysine in practical diets by young channel catfish Ictalurus punctatus. Two experiments were conducted in an attempt to explain this. In experiment 1, diets based on soybean meal or peanut meal-corn gluten meal supplemented with L-lysine HCl were fed to channel catfish (1.7 g average weight) either two or five times daily. The diet containing protein-bound lysine from soybean meal allowed greater weight gains than the diet supplemented with free lysine, and fish fed five times daily grew faster than fish fed twice daily. The interaction between lysine source and feeding frequency was not significant, indicating that feeding frequency did not affect the utilization of free lysine relative to that of protein-bound lysine. In experiment 2, ingesta were collected from the stomachs of fish at various times after feeding. The ratio of lysine to chromic oxide in ingesta from fish fed the free lysine-supplemented diet decreased with time, whereas no change occurred in this ratio in fish fed the protein-bound lysine diet. This indicates that free lysine passed from the stomach more rapidly than protein-bound lysine and suggests that free lysine would be absorbed before protein-bound lysine.
92 citations
TL;DR: The results showed that sesame seed meal may be incorporated in carp diets up to 200 gkg-1 and 400 g kg-1 in raw and treated (fermented) forms respectively.
Abstract: Six isonitrogenous (350 g kg−1 crude protein) and isoenergetic (17573 kJ kg−1) experimental diets incorporating raw and fermented sesame (Seasamum indicum) seed meal at 200, 300, and 400 g kg−1 into a fishmeal based diet were fed to rohu Labeo rohita fingerlings for 60 days and the growth performance and feed utilization efficiency of the fish was studied. The antinutritional factor phytic acid, from raw sesame seed meal, could be reduced below detection limit by fermentation with lactic acid bacteria (Lactobacillus acidophilus). Fermentation of the oilseed meal resulted in reduction of the tannin content from 20 to 10 g kg−1. In terms of growth response, feed conversion ratio and protein efficiency ratio, a diet containing 400 g kg−1 fermented sesame seed meal resulted in a significantly (P < 0.01) best fish performance. In general, growth and feed utilization efficiencies of fish fed fermented sesame seed meal diets were superior to those fed raw oilseed meal diets. Apparent protein digestibility (APD) values decreased with increasing levels of raw oilseed meal. APD was, however, significantly (P < 0.01) higher at all levels of incorporation of fermented sesame seed meal, while diets containing raw oilseed meal resulted in poor protein and lipid digestibility. Carcass protein and lipid contents of fish fed fermented sesame seed meal diets increased with increasing level of incorporation, being highest with 400 g kg−1 fermented oilseed meal-containing diet. The results showed that sesame seed meal may be incorporated in carp diets up to 200 g kg−1 and 400 g kg−1 in raw and treated (fermented) forms respectively.
92 citations
TL;DR: The bioavailability of dietary P can be improved by fine grinding the bone in fish meals, and dietary acidification by citric acid significantly increased whole-body iron in a linear fashion.
Abstract: Juvenile rainbow trout Oncorhynchus mykiss (Walbaum) were fed six low-phosphorus (P) diets supplemented with two different sizes of ground fish bone-meals (fine, 68 μm or less; coarse, 250–425 μm) and a coarse bone-meal diet containing four levels of citric acid (0, 4, 8 or 16 g kg−1 diet) to investigate the effects of pH and bone particle size on P bioavailability The basal diet provided 34 g P kg−1 and bone-meal increased P contents to 54–60 g P kg−1 Coarse bone-meal diets supplemented with 0, 4, 8 or 16 g kg−1 of citric acid had pH values of 60, 57, 54 and 50, respectively Weight gain and whole-body water, protein and lipid contents were not influenced by bone-meal supplementation Supplementing the basal diet with both coarse and fine bone-meal significantly increased whole-body ash content Fish fed no bone-meal were hypophosphataemic compared with fish fed with either fine or coarse bone-meals Phosphorus in fine bone-meal had higher availability than P in coarse bone-meal Bone-meal supplementation significantly decreased whole-body manganese content from 89 μg g−1 in fish fed no bone-meal to 23 and 45 μg g−1 in fish fed with fine and coarse bone-meals, respectively The concentration of magnesium increased but zinc concentration was not affected by bone-meal supplements Citric acid increased whole-body ash content but the influence of citric acid on the body P content was not significant (P = 007) Dietary acidification by citric acid significantly increased whole-body iron in a linear fashion The bioavailability of dietary P can be improved by fine grinding the bone in fish meals
92 citations
TL;DR: Dietary CHOL supplements profoundly altered excretion and liver metabolism of individual fatty acids in salmon and the impact of this alteration on physiological performance has not been elucidated.
Abstract: The influence of dietary cholesterol (CHOL) and short-chain fatty acids (SCFA; sodium salts of acetic, propionic and butyric acid, 5:5:2 w/w/w) on growth, organ indices, macronutrient digestibility, and fatty acid composition of Atlantic salmon Salmo salar was investigated. Salmon (initial average weight 0.7 kg) held in seawater (7°C) for 175 days were fed one of six diets: 1, without CHOL/SCFA supplement; 2, with 0.5% SCFA; 3, with 2.0% SCFA; 4, with 1.0% CHOL; 5, with 1.0% CHOL and 0.5% SCFA; 6, with 1.0% CHOL and 2.0% SCFA.
Neither SCFA nor CHOL supplements had any significant effects on specific growth rate (SGR), mortality, apparent digestibility coefficients (ADC) of macronutrients, total lipid content. Hepatosomatic index (HSI) was slightly increased in salmon fed the CHOL supplement (P < 0.05). Hepatic CHOL concentration, but not the hepatic CHOL pool, was significantly increased (P < 0.001) by dietary CHOL supplementation.
The fatty acid compositions of fillet and gut tissues were not influenced by dietary treatment, while significant effects of CHOL supplements were observed in faeces and liver. Less saturated fatty acids and more mono- and poly-unsaturated fatty acids were excreted with faeces in salmon fed CHOL supplements. Salmon fed CHOL supplements significantly reduced the relative concentration of hepatic palmitic acid (C16 : 0), arachidonic acid (C20 : 4 n-6) and docosahexaenoic acid (C22 : 6 n-3), while the contents of oleic acid (C18 : 1 n-9) and eicosenoic acid (C20 : 1 n-9) were significantly increased. SCFA did not influence the observed effects of dietary CHOL.
The present study shows that dietary CHOL supplements profoundly altered excretion and liver metabolism of individual fatty acids in salmon. The impact of this alteration on physiological performance has not been elucidated.
TL;DR: The A/E ratios have been hitherto utilized for the estimation of essential amino acid requirements in three salmonids, common carp and channel catfish: the present findings extend the validity of the method to other fish species.
Abstract: An experiment was conducted in a closed system to quantify the arginine requirement of juvenile silver perch Bidyanus bidyanus. Five experimental diets were formulated to contain 40% crude protein with five graded levels of arginine. The diets contained casein and gelatine as protein sources supplemented with crystalline L-amino acids to simulate the reference amino acid profile (except for arginine) of silver perch tissue protein. The experiment lasted 12 weeks and, based on growth data using broken-line analysis, the arginine requirement of juvenile silver perch was found to be 2.7 g 100 g−1 dry diet (or 6.8% of protein).
Based on whole-body amino acid composition, A/E ratios (essential amino acid/total essential amino acids + (cystine + tyrosine) × 1000) were estimated. Using the experimentally determined requirement for arginine and A/E ratios, the phenylalanine requirement of silver perch was predicted to be 5.5 g 100 g−1 protein. Another feeding trial was conducted to determine the phenylalanine require-ment of silver perch using a series of diets with various amounts of phenylalanine and a protocol similar to the previous one. It was found that the experimentally determined phenylalanine requirement of juvenile perch was similar to that predicted. The A/E ratios have been hitherto utilized for the estimation of essential amino acid requirements in three salmonids, common carp and channel catfish: the present findings extend the validity of the method to other fish species.
Journal Article•
TL;DR: In this paper, the relative importance of nutrient composition and levels of antinutritional factors present in various canola protein products derived from the processing of commercial canola meal (CCM) on digestibility in rainbow trout held in 9.9-11 degrees C fresh water was assessed.
Abstract: This study was undertaken to assess the relative importance of nutrient composition and levels of antinutritional factors present in various canola protein products derived from the processing of commercial canola meal (CCM) on digestibility in rainbow trout held in 9.9-11 degrees C fresh water. Laboratory sieving of CCM (SCM) reduced levels of crude fibre, cellulose and hemicellulose by 31.6%, 16.6% and 56.4%, respectively. Aqueous methanol-ammonia washing of sieved canola meal (ACM) increased neutral detergent fibre (NDF, insoluble dietary fibre) and phytate, and dramatically decreased levels of total glucosinolates (> 88%) and phenolic compounds (approximately equal to 59%) relative to CCM. Further treatment of ACM with phytase in acidified (pH 5.0) aqueous media (PCM), followed by filtration, increased levels of crude protein, crude fibre and NDF, and decreased levels of phytate (33%), phenolic compounds (81%) and glucosinolates (below detection limit) relative to CCM. Additional treatment of PCM with carbohydrase enzymes (SP-249 and/or Alpha Gal, an oligosaccharide-degrading enzyme) further elevated levels of NDF, cellulose, protein (SP-249 only) and indispensable amino acids (SP-249/Alpha Gal), and concurrently decreased levels of phytate relative to PCM. An industrial source of canola protein isolate (CPI), produced by first extracting CCM with aqueous salt solution and then recovering the protein fraction, had the best nutrient composition and lowest levels of the antinutritional factors mentioned above. The processing protocols had slight or marked negative effects (ACM and SP-249/Alpha Gal) on apparent dry matter digestibility. Protein digestibility coefficients were unaltered in the laboratory-processed products, except for the products treated with SP-249 and SP-249/Alpha-Gal. In these cases, the protein digestibility coefficients (77.4% and 79.5%) were significantly below that found for CCM (88.1%). With two of the treatments, ACM and SP-249/Alpha-Gal, processing depressed DE. In contrast, the DE level in CPI (20.6 MJ kg(-1)) and the digestibility coefficients for dry matter (77.1%) and protein (97.6%) were high. We conclude that high levels of fibre, either alone or together with phytate, have the greatest adverse effects on the digestibility of canola protein products for rainbow trout. The high digestibility of CPI and its low content of antinutritional factors may also enable this protein product to be an excellent substitute for premium quality fish meal in diets for salmonids.
TL;DR: In this paper, the dietary vitamin E requirement of juvenile hybrid striped bass (Morone chrysops female x Morone saxatilis male) was determined for 12 weeks.
Abstract: This study was conducted to determine the dietary vitamin E requirement of juvenile hybrid striped bass (Morone chrysops female x Morone saxatilis male). Semi-purified diets supplemented with 0.2 mg Se kg(-1) from Na(2)SeO(3) and either 0 (basal), 10, 20, 40, 60, or 80 mg vitamin E kg(-1) as DL-alpha-tocopheryl acetate were fed to hybrid striped bass initially averaging 1.8 +/- 0.1 g (mean +/- SD) for 12 weeks. Fish fed the basal diet, which contained 5.8 mg alpha-tocopherol kg(-1) dry weight, were darker in colour and had reduced weight gain, as well as generally reduced haematocrit values compared with fish fed diets supplemented with vitamin E. In addition, fish fed diets containing less than 20 mg supplemental vitamin E kg(-1) had significantly (P < 0.05) reduced weight gain and feed efficiency compared with those fed diets supplemented with vitamin E at 20-80 mg kg(-1). Dietary supplementation of vitamin E caused incremental increases in the concentration of alpha-tocopherol in both plasma and liver tissues. However, hybrid striped bass fed graded levels of vitamin E did not exhibit a dose response in terms of ascorbic acid-stimulated lipid peroxidation of hepatic microsomes. Regression analysis of weight gain data using broken-line model indicated a minimum vitamin E requirement (+/- SE) of 28 (+/- 3) mg kg(-1) dry diet. Based on these data, the dietary vitamin E requirement of hybrid striped bass appears to be similar to that determined for other fish species.
TL;DR: The dietary requirement of the prawn Penaeus monodon for linoleic and linolenic fatty acids was examined in the absence of other long-chain polyunsaturated and highly unsaturated fatty acids and the lipid content of the DG was highest in prawns fed diets containing both LOA and LNA, similar to the growth response.
Abstract: The dietary requirement of the prawn Penaeus monodon for linoleic (LOA) and linolenic (LNA) fatty acids was examined in the absence of other long-chain polyunsaturated and highly unsaturated fatty acids (PUFA-20:2, 20:3, 22:2, 22:3 and HUFA-18:4, 20:4, 20:5, 22:4, 22:5, 22:6, respectively). Incremented dietary amounts of LOA (7, 14, 21, 28 and 35% of total fatty acids) and LNA (0, 7, 14, 21 and 28% of total fatty acids) were examined in a 5 × 5 factorial growth experiment lasting 50 days. An additional diet containing both PUFA and HUFA (cod-liver oil) was provided as a reference. The total lipid content (excluding sterols) of each of the 26 diets was maintained at 70 g kg of dry diet. The fatty acid composition of the neutral lipid was manipulated by blending different plant oils and supplementing with purified free fatty acids to provide the desired fatty acid composition upon addition to the total diet. At the end of the 50-day growth experiment, the prawn digestive gland (DG) was quantitatively analysed for lipid and fatty acid content. Prawns fed the reference diet increased in weight (mean ±SEM) by 214 ± 6%. Growth was generally greater when combinations of LOA and LNA were used. The best growth (213 ± 17%) was obtained with the diet containing a fatty acid content of 14% LOA and 21% LNA. This growth was comparable to that of the reference diet. The digestibility of the total lipid in the diet was usually higher when both fatty acids were present. The lipid content of the DG was highest in prawns fed diets containing both LOA and LNA, similar to the growth response. The fatty acid composition of the prawn's DG lipid reflected the fatty acid composition of the diet. However, the maximum assimilation of LNA in the DG lipid (14.2% of DG lipid fatty acids) was about half that of LOA (32.5% of DG lipid fatty acids).
TL;DR: Growth, haemoglobin and element status were compared in Atlantic salmon fed a practical fish-meal based diet, unsupplemented or supplemented with a mixture of the elements zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) from first feeding as mentioned in this paper.
Abstract: Growth, haemoglobin and element status were compared in Atlantic salmon fed a practical fish-meal based diet, unsupplemented or supplemented with a mixture of the elements zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) from first feeding (weight 0.20 g). The diets were fed to triplicate groups of fish from weeks 1–20 and to duplicates from weeks 21–34. The basal diet (Diet 1) was not supplemented and contained 67 mg Zn, 106 mg Fe, 4.7 mg Mn and 3.7 mg Cu kg–1. Diet 2 was supplemented with 68 mg Zn, 34 mg Fe, 13 mg Mn and 3.5 mg Cu kg–1. Iron was not added to Diet 3.
Mean weight and mortality did not differ among the groups at any sampling point. Whole-body Zn and Mn responded to dietary concentration at all sampling points. Plasma and vertebrae Zn concentrations responded significantly to dietary Zn concentration. There were no effects with Fe. The Fe status of the fish, assessed by whole-body and liver Fe concentrations, was low in all groups. No effect of supplementation was found for Cu and no accurate judgement either of status or requirement could be made from the present results.
It is concluded that supplementing fish-meal based start feeds for Atlantic salmon with Zn, Mn and Fe is appropriate, while further studies are needed for the evaluation of Cu supplementation. The supplementation levels used in the present experiment appeared to meet the requirements for Zn and Mn, while the supplemented level of Fe appeared to be too low. Deleting Fe from the element mixture did not significantly affect Fe status or that of Zn, Mn and Cu.
There was an accumulation of Zn and Fe with growth. Cu remained constant and there was a trend towards reduced Mn in the fish given the unsupplemented diet.
TL;DR: The combination of protease inhibition assays with measurements of DH and CPD is proposed as a preliminary evaluation of protein ingredients used in the formulation of artificial feeds for larval fish.
Abstract: The development of artificial feeds for marine fish larvae is demanding and, taking into account the diAculties and costs associated with the rearing of the larvae of some fish, preliminary evaluation of feed ingredients using in vitro techniques may be an alternative to in vivo assays. Some proteins used in microfeeds for marine fish were tested in vitro for examination of their eAect on the proteases of seabream larvae. Casein and cuttlefish meal did not aAect protease activity of crude larval extracts, whereas ovalbumin 1 produced a 60% inhibition. The use of a pH-stat for the assessment of the degree of hydrolysis (DH) of proteins confirmed the low nutritive value of ovalbumin, since a much lower value was obtained for microcapsules prepared using this protein source when compared with those prepared using casein or cuttlefish meal (3.2 vs. 7.3 and 7.6, respectively). Products resulting from such hydrolysis were analysed using sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐ PAGE). Image analysis of such gels led to the formulation of an index named the coeAcient of protein degradation (CPD) which expressed the extent to which the main protein fractions were hydrolysed by larval proteases in a given time. A significant correlation (r 2 a 0.98, P < 0.05) was obtained between DH and CPD values measured for either protein sources or microcapsules. The combination of protease inhibition assays with measurements of DH and CPD is proposed as a preliminary evaluation of protein ingredients used in the formulation of artificial feeds for larval fish.
TL;DR: It was found, in this study, that up to 75% protein of fish meal can be replaced with the protein of dehulled lupin seed meal in diets for juvenile P. monodon.
Abstract: An indoor feeding trial in a flow-through marine water system was performed to evaluate the feasibility of using dehulled lupin Lupinus albus seed meal as a protein source to replace fish meal in diets for the juvenile Penaeus monodon. Five isonitrogenous (40% crude protein) diets formulated by replacing 0, 25, 50, 75, and 100% of fish meal protein by lupin meal protein were fed to shrimp (mean initial weight of 4.32 ± 0.23 g) three times daily at a feeding allowance of 5% body weight per day for 42 days. Shrimp fed diets with 0, 25, 50 and 75% replacement had similar (P > 0.05) weight gain, dry matter feed intake, feed conversion ratio (FCR), protein efficiency ratio (PER), and apparent net protein utilization (ANPU). Shrimp fed the highest dietary inclusion level of lupin meal (100% replacement) had significantly (P 0.05) in whole-body composition (dry matter, protein, lipid and ash) of shrimp fed on the various diets. Pellet water stability was inversely related to level of lupin meal inclusion. It was found, in this study, that up to 75% protein of fish meal can be replaced with the protein of dehulled lupin seed meal in diets for juvenile P. monodon. The diet with total replacement of fish meal containing 40% lupin meal was utilized very poorly by the shrimp.
TL;DR: No significant differences in vitamin losses during storage were found between pelleted and extruded feeds, however, losses of ascorbic acid, menadione and pyridoxine in both manufactured feeds were much greater in crystalline than in coated forms.
Abstract: The stability of two forms of vitamins, crystalline and fat-coated, during manufacturing processes and storage of fish feeds was investigated. After extrusion, vitamin recovery was generally lower than that found after pelleting. The recovery of coated forms after pelleting was higher than that of crystalline ones, especially for ascorbic acid, menadione, pyridoxine and folic acid. Coated forms were also found to be more resistant to extrusion than crystalline forms. No significant differences in vitamin losses during storage were found between pelleted and extruded feeds. However, losses of ascorbic acid, menadione and pyridoxine in both manufactured feeds were much greater in crystalline than in coated forms.
TL;DR: Individual plant protein feedstuffs were incorporated into a diet containing fish meal and fed to rainbow trout to determine apparent and true phosphorus availability (APA and TPA, respectively) and values for the plant protein ingredients of over 100%.
Abstract: Individual plant protein feedstuAs were incorporated into a diet containing fish meal and fed to rainbow trout to determine apparent and true phosphorus availability (APA and TPA, respectively). The plant protein feedstuAs evaluated were soybean, canola and peanut meals; each was incorporated at 200 g kg ‐1 of dry matter. The average initial weight of fish was 68 g and the water temperature was maintained at 15∞C. Concentrations of macronutrients were constant in diets. Incorporation of plant protein feedstuAs significantly increased APA and TPA values. The APA values were 19.5% for fish meal and 39.5%, 40.2%, and 38.5% for the diets containing soybean meal, canola meal, and peanut meal, respectively. Similarly, the TPA values for the combination of fish meal and plant protein feedstuA were 43.4%, 42.1% and 40.6% for diets containing soybean, canola and peanut meals, respectively, which were significantly higher than values for fish meal (21.5%). Calculation of APA and TPA values for individual feedstuAs resulted in values for the plant protein ingredients of over 100%. We speculate that the increased APA and TPA values were the result of decreasing total dietary phosphorus concentrations or dilution of the calcium concentrations from bone in fish meal.
TL;DR: Regression analysis of weight gain data using the broken-line model resulted in a minimum vitamin C requirement (+/-SE) of 15 +/- 3 mg kg-1 diet, which was undetectable in liver of fish fed the basal diet while liver ascorbate levels in fish feeding the other diets generally reflected dietary supplementation.
Abstract: A feeding trial was conducted to determine the minimum dietary vitamin C requirement of juvenile red drum and characterize signs of vitamin C deficiency. Semipurified diets containing 400 g crude protein kg-1 from lyophilized red drum muscle and crystalline amino acids were used in the feeding trial. The basal diet without supplemental vitamin C contained approximately equal to 6 mg vitamin C kg-1 and was fed for a 1-week conditioning period. Red drum, initially averaging approximately equal to 3.6 g each, were fed diets supplemented with 0, 10, 20, 30, 45, 60, 75, or 150 mg vitamin C kg-1 as ascorbate polyphosphate for a period of 10 weeks. Fish fed the basal diet began to exhibit overt signs of vitamin C deficiency, including reduced weight gain, lordosis, scoliosis and loss of equilibrium after 8 weeks. Total ascorbate was undetectable in liver of fish fed the basal diet while liver ascorbate levels in fish fed the other diets generally reflected dietary supplementation. Regression analysis of weight gain data using the broken-line model resulted in a minimum vitamin C requirement (+/-SE) of 15 +/- 3 mg kg-1 diet.
TL;DR: Analysis of zooplankton showed that both essential and nonessential amino acids were present at a level that was higher than control diet, and heavy metals concentrations were at very low levels in fish fed on wastewater-grown zoopLankton.
Abstract: Zooplankton grow in the last stage of water purification at the Werribee Sewage Treatment Lagoons (WSTL) and the resource is huge and unutilized. Daphnia carinata and Moina australiensis are the dominant species at the WSTL. The protein content of D. carinata and M. australiensis was 54.80% and 64.80%, respectively. Analysis of zooplankton showed that both essential and nonessential amino acids were present at a level that was higher than control diet. Silver perch fed on D. carinata exhibited better growth, better food conversion ratio (FCR), protein efficiency ratio (PER) and apparent net protein utilization (ANPU), which were not significantly different from the control diet (P > 0.05). Heavy metals concentrations were at very low levels in fish fed on wastewater-grown zooplankton.
TL;DR: Diets deficient in ascorbic acid, biotin, folic acid, niacin, thiamin and α-tocopherol resulted in poor appetite and poorer feed conversion efficiency, and all treatments except the control resulted in histopathological changes in the digestive gland cells.
Abstract: The effect of deletion of individual water-soluble (thiamin, riboflavin, pyridoxine, cyanocobalamin, pantothenic acid, folic acid, niacin, biotin, choline, inositol and ascorbic acid) and fat-soluble vitamins (vitamins A, D, E and K) in semipurified diets on growth and survival of juvenile shrimp, Penaeus monodon, was studied in the laboratory for 8 weeks. Diets lacking riboflavin and vitamin K did not affect growth and survival of shrimp. However, deletion of inositol and choline in the diet resulted in poor growth. Maximum growth was observed in the control diet (C1) supplemented with all vitamins. Diets deficient in ascorbic acid, biotin, folic acid, niacin, thiamin and α-tocopherol resulted in poor appetite and poorer feed conversion efficiency. All treatments except the control (C1) resulted in histopathological changes in the digestive gland cells. Detachment or destruction of the epithelial cells was observed in all treatments lacking individual vitamins but more severely in the treatment without a vitamin supplement, followed by inositol, choline and ascorbic acid deficient diets.
TL;DR: The acceptability, digestibility and nutrient utilization of feeds containing cocoa husk were determined for tilapia Oreochromis niloticus fingerlings reared in a recirculation system and it was found that the consumption of the cocoa husK feeds could compensate for their low digestibility under acceptable fish yields and returns.
Abstract: The acceptability, digestibility and nutrient utilization of feeds containing cocoa husk were determined for tilapia Oreochromis niloticus fingerlings reared in a recirculation system. Three semipurified isonitrogenous diets formulated to contain 0, 100 and 200 g kg−1 of cocoa husk were fed to satiation three times daily. Although the feeds containing cocoa husk were acceptable to the fish, as indicated by their voracious consumption and positive weight gains, there were significant (P 0.05) by the 100 g kg−1 cocoa husk feed treatment. The consumption of the cocoa husk feeds could compensate for their low digestibility under acceptable fish yields and returns.
TL;DR: The reference diet supported excellent prawn growth when fed with ad libitum or subsatiation, and the effects of either a purified reference experimental diet, a practical experimental diet and an imported commercial diet on the growth and nutritional condition of the prawn Penaeus monodon were compared.
Abstract: Critical evaluation of the nutrient requirements of an animal requires the use of a purified reference diet. In this study, the effects of either a purified reference experimental diet, a practical experimental diet and an imported commercial diet on the growth and nutritional condition of the prawn Penaeus monodon were compared. The reference diet, based on widely available ingredients of consistent and known nutrient content, supported excellent prawn growth when fed with ad libitum or subsatiation (approximately equal to 75% of the mean initial satiation intake). In a 6-week experiment, growth (as percentage increase in weight, +/- SEM) of the prawns fed ad libitum differed significantly (P 0.05) different from that obtained with the same diet fed ad libitum. Dry matter food conversion for the reference diet was significantly (P 0.05) different from each other. The lipid content (mg g(-1) of prawn) of the digestive gland of prawns fed ad libitum was similar for reference, practical and commercial diets (6.03 +/- 0.38, 4.92 +/- 0.90 and 4.92 +/- 0.95 mg g(-1) of prawn, respectively), but significantly (P < 0.05) higher than that for the reference diet fed subsatiation (4.73 +/- 0.38 mg g(-1) of prawn).
TL;DR: The in vitro metabolism of 14CD3 and 3H25OHD3 was investigated in different tissues from Atlantic salmon Salmo salar, Atlantic mackerel Scomber scombrus, Atlantic halibut Hippoglossus hippoglossUS and Atlantic cod Gadus morhua, suggesting a lower degree of specificity in fish organs than in human organs.
Abstract: The in vitro metabolism of 14CD3 and 3H25OHD3 was investigated in different tissues from Atlantic salmon Salmo salar, Atlantic mackerel Scomber scombrus, Atlantic halibut Hippoglossus hippoglossus and Atlantic cod Gadus morhua. The tissues analysed were liver, kidney, head kidney, gills, spleen and intestine. The metabolites were extracted in methanol–chloroform and separated by normal-phase high-pressure liquid chromatography (HPLC) followed by scintillation counting. Identification of the metabolites was by comigration with standards on normal and reversed-phase HPLC systems and by protein-binding assays. All tissues from all species analysed produced hydroxylated derivatives identified as 25OHD3, 24,25(OH)2D3 and 1,25(OH)2D3. In addition, some unidentified derivatives were recorded, one probably being 25,26(OH)2D3. Organs producing great amounts of one metabolite also produced considerable amounts of the other possible derivatives, suggesting a lower degree of specificity in fish organs than in human organs. The predominating metabolite was 24,25(OH)2D3 in all organs from salmon and mackerel during incubation with 14CD3 and within most organs from all species during 3H25OHD3 incubation. The latter observation probably results from the need for decreasing rather than increasing the calcium absorption in these species, which live at least some periods of life in a marine environment.
TL;DR: A culture trial was performed using five levels of ascorbic acid 2-monophosphate in a semipurified diet for early postlarval Penaeus vannamei and found an optimal dietary level of 130 mg AA kg−1 diet, which showed significantly better growth according to dietary AA level after 25 days of feeding.
Abstract: A culture trial was performed using five levels of ascorbic acid 2-monophosphate (AmP at 0, 10, 100, 1000 and 2000 mg kg−1 diet, expressed as active ascorbic acid, AA) in a semipurified diet for early postlarval Penaeus vannamei. The experiment started 10 days after metamorphosis of the mysid larvae into postlarvae (=PL10). Each treatment was run in four replicates. P. vannamei postlarvae showed significantly better growth according to dietary AA level after 25 days of feeding, i.e. at PL36 stage. Whereas the dry weight of PL36 in the control treatment (0 mg AA kg−1 diet) was only 2 mg, supplementation of 1000 mg AA kg−1 increased the shrimp dry weight up to 18 mg. However, the growth in the other treatments was not significantly different from the control. Fitting a broken-line regression to the biomass yield demonstrated an optimal dietary level of 130 mg AA kg−1 diet. There were no differences observed among the treatments in stress resistance of postlarval P. vannamei to a salinity shock.
TL;DR: In this paper, the growth, food utilization and amounts of nitrogen and phosphorus lost into the water by rainbow trout (initial size 485g) fed on low-fat Baltic herring and supplemented with a low-protein dry diet fed separately were studied in an 18-week net cage trial.
Abstract: The growth, food utilization and amounts of nitrogen and phosphorus lost into the water by rainbow trout (initial size 485 g) fed on low-fat Baltic herring and supplemented with a low-protein dry diet fed separately were studied in an 18-week net cage trial. Similarly to balancing protein and nonprotein energy in full diets, giving nonprotein energy in different feeds several hours apart improved the protein retention of low-fat herring to a level comparable to a commercially available dry diet control. The amounts of nitrogen and phosphorus lost into the water were also reduced to the same extent. The losses from the plain herring-feeding were twice as high. The improved protein retention and reduced nutrient losses were accompanied by 15–25% reductions in growth of the fish compared with the control dry diet. The growth of the fish fed on plain herring was 14% lower than the growth on the dry diet control.
TL;DR: The absolute content of every sterol decreased in spat that had been starved for 6 weeks, but the relative sterol composition was similar to the initial sterol profile, indicating the important role of this sterol in spat metabolism.
Abstract: Pacific oyster Crassostrea gigas spat were fed either the microalga Chaetoceros muelleri, Isochrysis aff. galbana (strain T-IS0) or Pavlova lutheri to investigate the effect of dietary phytosterols on the sterol composition of spat tissues. After a 6-week feeding period the sterol profile of spat tissues generally reflected that of the diet, but not all sterols were assimilated with the same efficiency. 4-Desmethyl sterols, such as cholesterol and 24-methylcholesterol, were readily incorporated into spat tissues but 4-methyl sterols, such as 4-methyl-24-ethyl-5α-cholest-22E-en-3β-ol and the unusual 3,4-dihydroxy 4-methyl sterol 24-methylpavlovol present in P. lutheri, were poorly assimilated by spat. The absolute content of every sterol decreased in spat that had been starved for 6 weeks, but the relative sterol composition was similar to the initial sterol profile. However, the relative level of cholesterol increased, indicating the important role of this sterol in spat metabolism.