Showing papers by "Rowett Research Institute published in 1986"
TL;DR: For most grain, except corn and sorghum, 90% or more of starch is normally fermented in the rumen as mentioned in this paper, and the capacity for digestion of raw starch in the small intestine is limited to 100 to 200 g/d in sheep.
Abstract: For most grain, except corn and sorghum, 90% or more of starch is normally fermented in the rumen With corn, up to 30% or more could escape ruminal fermentation; most of the starch escaping fermentation would be digested in the small intestine or fermented in the large intestine The capacity for digestion of raw starch in the small intestine is limited to 100 to 200 g/d in sheep Gelled starch could be digested in quantities up to 200 to 300 g/d The capacity would ultimately be limited by lack of enzymes involved in hydrolysis of short chain di- and oligosaccharides and also by capacity for absorption of glucose Starch fermented in the cecum leads to an increase of N loss in the feces In some instances, the high propionic acid proportion arising from fermentation of starch exceeds the capacity of the liver for metabolism In growing lambs and goats, this creates problems of synthesis of branched-chain fatty acids in adipose tissue and, in dairy cows, problems of low milk yield and milk fat production The low ruminal pH that often occurs when starchy grain is included in diets for ruminants can cause depression in fiber digestion Some of these problems can be overcome by reducing extent of cereal processing and other methods that prevent low ruminal pH It is concluded that due to limited capacity for starch digestion postruminally and high animal variability, deliberate attempts to increase postruminal digestion of starch are unlikely to be beneficial and are likely to create potential digestive problems
378 citations
TL;DR: It is concluded that the growth-promoting effect of clenbuterol may be specific to muscle and that the drug may act in a novel manner which circumvents the physiological mechanisms responsible for the control of muscle growth.
Abstract: 1. Young rats were offered to appetite a semi-synthetic diet either alone or containing the beta 2-selective agonist clenbuterol (4-amino-alpha[t-butylamino)methyl]-3,5-dichlorobenzyl alcohol). 2. In female rats (starting weight 116g) the presence of the drug at daily doses greater than 10 micrograms/kg body-weight per d increased the growth of skeletal and cardiac muscle but had no stimulatory effect on the growth of the liver, gastrointestinal tract and kidney. 3. Male rats (starting weight 53 g) received clenbuterol at a daily oral dose of 200 micrograms/kg body-weight per d. Animals were slaughtered after 0, 4, 8, 11, 18, 21 and 25 d of treatment. At 4, 11, 21 and 25 d muscle protein synthesis was measured by the method of Garlick et al. (1980). Although clenbuterol increased the rate of protein and RNA accretion in gastrocnemius and soleus muscles, protein synthesis was not increased. 4. The results suggested that the drug had a rapid, perhaps direct, inhibitory effect on protein degradation. It is concluded that the growth-promoting effect of clenbuterol may be specific to muscle and that the drug may act in a novel manner which circumvents the physiological mechanisms responsible for the control of muscle growth.
312 citations
TL;DR: An extracellular cellulase which was highly active in solubilizing the highly hydrogen bond-ordered cellulose in cotton fibre was found in a culture filtrate of the anaerobic fungus, Neocallimastix frontalis, isolated from the rumen of a sheep.
Abstract: An extracellular cellulase which was highly active in solubilizing the highly hydrogen bond-ordered cellulose in cotton fibre was found in a culture filtrate of the anaerobic fungus, Neocallimastix frontalis, isolated from the rumen of a sheep. The cellulase was several-fold more active in solubilizing cotton fibre per unit of endo-1,4-β-glucanase than the cellulase of the aerobic fungus Trichoderma reesei mutant strain C-30, which is one of the most active cellulases isolated so far.
162 citations
TL;DR: In this article, four cows in early lactation were given continuous infusion into the abomasum of 0, 200, 400 or 600 g lactic casein/d according to a Latin-square design.
Abstract: 1. Four cows in early lactation were given continuous infusion into the abomasum of 0, 200, 400 or 600 g lactic casein/d according to a Latin-square design. Each period was of 14 d and the Latin square was followed by 7 d in which an infusion of 800 g glucose/d was given. The basal diet was given at a level which provided sufficient nitrogen and energy for 10 kg milk yield/d.2. Infusion of casein resulted in significant increases in milk yield, milk N yield and milk energy yield; milk N increased progressively but milk energy reached a maximum at 400 g casein/d. Milk yields and composition when glucose was infused resembled those seen on the zero casein treatment.3. N-balance measurements indicated a severe deficit (–20 g/d) on the zero casein treatment and a progressive increase to +7 g/d as casein increased; N equilibrium was achieved at about 400 g casein/d. The regression of net productive N on N intake (P < 0.001) indicated that the efficiency of utilization of dietary N did not differ between treatments.4. Heat production increased with increase in casein infused (P < 0.05) but remained a constant proportion of the metabolizable energy (ME) intake. Energy balances were negative and did not differ significantly between treatments but calculation of the protein and fat components indicated a threefold increase in body fat mobilization in response to the first increment of casein. Milk yield adjusted to zero energy balance was significantly related to ME intake (P < 0.001) but the efficiency of encrgy utilization was not affected by the level of casein infusion.5. The concentrations of glucose, β-hydroxybutyrate and non-esterified fatty acids in plasma did not differ between treatments but the concentration of urea in plasma increased markedly (P < 0.05) at the highest level of casein addition. Insulin concentrations increased and growth hormone decreased (both P < 0.05) with increase in casein infusion.6. The concentration of total amino acids (AA) in plasma increased up to 400 g casein/d and then declined. Changes in concentration and in the ratio of essential: total AA indicated a very high extraction rate of essential AA at the lower levels of casein infusion.7. The observed lactational responses are discussed in relation to the ratio of protein:energy in the absorbed nutrients. It is concluded that the primary response to casein was the correction of an AA deficit and that body fat mobilization was secondary and occurred in response to the high ratio of AA-N:energy in the infused casein.
137 citations
TL;DR: De Boever et al. as discussed by the authors used the use of an enzymatic technique to predict digestibility, metabolizable and net energy of compound feedstuffs for ruminants.
129 citations
TL;DR: There were no between-treatment or between-period differences in the disappearance of 35S-labelled bacteria from the small intestines of infected or control lambs, but the infection did cause an increase in plasma N leakage during both periods.
Abstract: 1. Ten 5-month-old lambs (29 (SE 1.2) kg), reared parasite-free and prepared with rumen duodenal and ileal cannulas, were paired and given rations of Ruminant Diet AA6 (90 g/kg live Weight0.75) by means of continuous feeders. From 6 months of age one of each pair was dosed daily with 2500 Trichostrongylus colubriformis larvae for 14 weeks. Untreated animals received the amount of ration consumed by their infected pair-mates the previous day.2. During three periods, ((1) the week before and the first 2 weeks of dosing with infected larvae, (2) during weeks 5–7 and (3) during weeks 11–13 of dosing) all lambs underwent a series of experiments to determine their nitrogen balance, the amounts of N leaving the small intestine, the amount of 51CrC13-labelled plasma protein leaking into the small intestines, and the disappearance of 35S-labelled bacteria from the small intestine.3. The infection caused varying degrees of feed refusal in all infected animals. As a result the values for N balance and for the flow of N at the ileum during the latter two periods were regressed against dry-matter intakes for each group in each period.4. The infection caused a reduction (P < 0.05) in N retention and increased (P < 0.05) flow of N at the ileum. The increase in N flow at the ileum of infected lambs was greater (P < 0.01) at weeks 11–13 of dosing (infected–control 3.6 g N/d (standard error of difference (SED) 0.57), P < 0.01) than at weeks 5–7 of dosing (infected–control 1.5 g N/d (SED 0.57), P < 0.05).5. There were no between-treatment or between-period differences in the disappearance of 35S-labelled bacteria from the small intestines of infected or control lambs, but the infection did cause an increase in plasma N leakage during both periods. During weeks 5–7 and 11–13, plasma N leakage in infected lambs was 1.1 g N/d (P < 0.01) and 1.7 g N/d (P = 0.056) respectively higher than that in the control lambs.6. A proportion of the endogenous secretions which enter the small intestine is likely to be resorbed before the ileum. It was calculated that to account for the extra non-ammonia-N (NAN) flow at the ileum up to 3–5 g NAN/d during weeks 5–7 of dosing and 15–20 g N/d during weeks 11–13 of dosing could have entered the small intestine as mucin and sloughed cells.7. The results seem to indicate that the nutritional penalty associated with the development of resistance to infection is greater than that associated with the primary infection.
120 citations
TL;DR: It is concluded that the response of muscle protein synthesis to food intake is mediated by both insulin and amino acids acting in concert.
Abstract: In 12 h fasted rats, rates of muscle protein synthesis were stimulated by refeeding for 1 h and by intragastric or intravenous infusion of an amino acid plus glucose mixture for 1 hr, but not by intravenous infusion of amino acids alone for 1 h. Intravenous injection of anti-insulin serum suppressed the response to feeding and to intragastric infusion, but not to intravenous infusion. It is concluded that the response of muscle protein synthesis to food intake is mediated by both insulin and amino acids acting in concert.
115 citations
TL;DR: The degradation of cell walls of mesophyll, epidermis and fibre cells isolated from leaves of perennial and Italian ryegrass within the sheep rumen or by selected strains of rumen bacteria in vitro, was followed by estimation of dry matter loss, or loss of neutral sugar residues.
Abstract: The degradation of cell walls of mesophyll, epidermis and fibre cells isolated from leaves of perennial and Italian ryegrass within the sheep rumen or by selected strains of rumen bacteria in vitro, was followed by estimation of dry matter loss, or loss of neutral sugar residues. Primary cell walls (mesophyll and epidermis) were fully degraded within 12 h in the rumen, while the more heavily lignified fibre cell walls showed only a 40% loss of dry matter over the same period. Neutral sugar residues were lost at a common rate from walls of all three cell types. Incubation of cell walls with cellulolytic bacteria showed that the extent to which cell walls were attacked was constantly ordered (epidermis > mesophyll > fibre). The rate of degradation of cell walls was less in axenic culture than within the rumen. Greatest weight losses were produced by Ruminococcus albus, followed by Bacteroides succinogenes, with Ruminococcus flavefaciens effecting the least change, regardless of the nature of the cell wall provided as a substrate. Xylose was more readily lost from primary cell walls than glucose during the early stages of attack, but both were lost at a common rate from fibre cell walls. Dry matter losses produced by the hemicellulolytic strain, Bacteroides ruminocola, were limited even after extended incubation. Electron microscopy indicated that R. albus was less commonly attached to cell walls than were the other cellulolytic strains, although evidence of capsular material was present. Bacteroides succinogenes was seen with an extensive capsule which enveloped clusters of cells, forming micro-colonies in association with the plant cell wall. Vesicle-like structures, commonly associated with the cellulolytic bacteria R. albus and B. succinogenes, were found on comparatively few occasions in this study.
111 citations
TL;DR: The effect of dietary administration of clenbuterol on soleus and extensor digitorum longus muscles was studied and both muscles showed an increase in wet weight with no significant change in total fibre number.
Abstract: The effect of dietary administration of clenbuterol on soleus and extensor digitorum longus muscles was studied after 4 and 21 days. Both muscles showed an increase in wet weight with no significant change in total fibre number. After 4 days fibre cross-sectional areas were increased in soleus, but not in extensor digitorum longus, and after 21 days there was a change in fibre frequencies in extensor digitorum longus but not soleus muscles.
109 citations
TL;DR: For all experiments the flow of N both from the rumen and abomasum was highly variable; this has to be considered if a constant value is used for endogenous N in estimating dietary N in the abomaum.
Abstract: 1. Three experiments were conducted to determine the flow of nitrogen through the rumen and abomasum when cows, steers and lambs were totally nourished on volatile fatty acids infused into the rumen. 2. In two dairy cows (650-700 kg) and two large steers (370-405 kg) the daily flow of non-ammonia-N (NAN) from the rumen was 50.7 and 58 mg/kg live weight (W)0.75 respectively. 3. The flows of NAN through the rumen and abomasum in four young steers (240-315 kg) were 85.0 (SE 21.0) and 195 (SE 7.0) mg/kg W 0.75 respectively. 4. In the third experiment the effects of altering rumen pH and osmotic pressure on flow of NAN through the rumen and abomasum were investigated in lambs. While rumen pH and osmotic pressure influenced rumen volume and outflow they had no significant effect on NAN flow. The mean values for NAN outflow from the rumen and abomasum were 76 and 181 mg N/kg W 0.75 respectively. 5. Abomasal NAN flow increased with increasing abomasal pH. When osmotic pressure was greater than about 330 mosmol/l in the rumen there was a net inflow of water, while below this value there was net loss of water. 6. For all experiments the flow of N both from the rumen and abomasum was highly variable; this has to be considered if a constant value is used for endogenous N in estimating dietary N in the abomasum. 7. With N-free infusion the rumen NH3 concentration varied from 50 to 120 mg NH3-N/l. 8. The amino acid composition of rumen and abomasal N was also determined. Relative to tissue N it contained a higher proportion of cysteine.
105 citations
TL;DR: The degradation characteristics of the hays were measured by incubating samples (in nylon bags) for 12, 24, 48 or 72 h in the rumen of four sheep fitted with rumen cannulae and given a good hay as discussed by the authors.
Abstract: The voluntary intake and digestibility of four hays were measured with eight sheep using two 4 × 4 Latin squares. Measurements were made during the last 8 days of each 3-week period. The degradation characteristics of the hays were measured by incubating samples (in nylon bags) for 12, 24, 48 or 72 h in the rumen of four sheep fitted with rumen cannulae and given a good hay. The exponential p = a + b(1 − e−α) where p = degradation loss, t = time, and a, b and c are constants, was fitted. The potential degradability (defined as a + b) of the dry matter (DM) of the four hays was 0·76, 0·66, 0·54 and 0·46 with corresponding voluntary intakes of 71, 62, 52 and 45 ± 2·9 g DM per kg M075 per day. The in vivo digestibilities were 0·61, 0·59, 0·46 and 0·45 (s.e. 0·013) respectively and corresponded to 23-, 25-, 31- and 67-h degradation. Voluntary intake was better related to potential degradability (and degradability at 12, 24, 48 and 72 h) than to in vivo digestibility. It is concluded that the degradation characteristics of forages may have useful application in predicting voluntary intakes, and that potential degradability could be used to define the rumen (jegradable nitrogen content necessary with any particular forage.
TL;DR: In this paper, two barley straws, Corgi and Gerbel, were chosen for further examination of botanical fractions and to see how each fraction responded to treatment with ammonia.
Abstract: Two varieties of barley straw, Corgi and Gerbel, which varied in degradability when incubated in the rumen in nylon bags, were chosen for further examination of botanical fractions and to see how each fraction responded to treatment with ammonia. The straws were separated into leaves, internodes, nodes and chaff. The average proportions of these fractions were respectively 0·499, 0·380, 0·055 and 0·065 in Corgi straw and 0·404, 0·512, 0·059 and 0·025 in Gerbel straw. For both varieties the degradability of the botanical fractions were leaves > chaff > nodes > internodes.Despite a similar chemical composition, the dry-matter loss (DML) values of leaves, internodes and nodes of Corgi were higher than those of Gerbel straw.The differences between varieties were larger for internodes and nodes than for leaves. The difference in DML of the two varieties at 48-h incubation was 132 g/kg DM. Of this difference, 25 g were due to differences in distribution of the botanical fractions and 107 g to differences in DML of the fractions.Ammonia treatment significantly increased the DML of all fractions except the nodes. The overall improvement due to ammonia treatment of the different fraction was internode > chaff > leaves > nodes.
TL;DR: The changes in neutrophil function and the severity of copper deficiency, in biochemical terms, induced by the molybdenum or iron treatments were greater than those induced by diets of low copper content.
TL;DR: Dietary administration of the growth promoter, clenbuterol, ameliorated denervation-induced atrophy in rat soleus muscles and inhibited the appearance of atrophy, and in chronically denervated muscles the atrophy was almost fully reversed.
Abstract: Dietary administration of the growth promoter, clenbuterol, ameliorated denervation-induced atrophy in rat soleus muscles. In acutely denervated muscles the drug inhibited the appearance of atrophy, and in chronically denervated muscles the atrophy was almost fully reversed. Responses in slow twitch oxidative fibres were particularly marked.
TL;DR: Selenium deficiency was demonstrated to impair the ability of mouse neutrophils to kill C. albicans in in vitro tests and the possible relationships of this defect in function to decreased resistance to C.Albicans infection is discussed.
Abstract: The effects of selenium deficiency on the responses to Candida albicans infection were examined in mice. When selenium-deficient and selenium-supplemented mice were given i.v. injections of 0.1 ml suspensions of 1 X 10(5) or 5 X 10(4) C. albicans in 0.9% sterile saline, deaths in the selenium-deficient animals started after 2.5-3.5 d compared with 7-8.5 d in the selenium-supplemented animals. Further studies demonstrated that 3 d after an i.v. injection of 1 X 10(5) C. albicans, significantly more of the microorganisms were found in the kidneys (P less than 0.001), livers (P less than 0.025) and spleens (P less than 0.01) of the selenium-deficient mice compared with the same organs of selenium-supplemented animals. Selenium deficiency was also demonstrated to impair the ability of mouse neutrophils to kill C. albicans in in vitro tests. The possible relationships of this defect in function to decreased resistance to C. albicans infection is discussed.
TL;DR: In this article, the dry-matter degradation of 19 varieties of barley, 14 varieties of wheat, 11 varieties of oats and one variety of triticale straws, both untreated and ammonia treated were studied using the nylon-bag technique.
Abstract: The dry-matter degradation of 19 varieties of barley, 14 varieties of wheat, 11 varieties of oats and one variety of triticale straws, both untreated and ammonia treated were studied using the nylon-bag technique. There were significant differences between the untreated varieties of all the types of cereal straw studied with respect to dry-matter loss (DML) values. When the barley and wheat straws were treated with ammonia, the differences between the varieties were also significant although ammonia treatment tended to improve those with lower values to a greater extent than those with higher values. There were also significant differences between the DML values of the oat straws when they were treated with ammonia but only after 48-h incubation. There was a significant negative relationship between the 48-h DML values of the untreated oat straws and the improvement in the DML values with ammonia treatment (r = −0·65; P < 0·05). Grain yield, straw length and nitrogen concentration had no significant relationship with the DML values of the untreated straws. Barley and oat straws had generally higher DML than the wheat and triticale straws.
TL;DR: A method is described to aid the prescription of diabetic diets, derived from newly available data for computation of metabolic rates of individuals, which is more accurate and more flexible than currently accepted methods of dietary assessment and should lead to improved use of dietetic resources.
TL;DR: This technique allows ewes to be used repeatedly as embryo donors and should be valuable to research workers and those involved with commercial embryo transfer in sheep.
01 Feb 1986
TL;DR: It would be impossible to devise a nutritional regimen which would simultaneously permit normal reproduction and maintain maternal body composition unchanged throughout, and the aim must be to produce balance in the composition of the body over the breeding cycle as a whole.
Abstract: Changes in the maternal body during reproduction are characterized by their diversity and this holds true for comparisons within as well as between species. The weights of some organs and tissues increase whereas others decrease and there is considerable variation in the magnitude of these changes (Hytten & hi tch , 1971). For interspecies comparisons the enormous differences in the quantitative expression of pregnancy and its failure to conform to any clear-cut generalization (Blaxter, 1964) makes it difficult to propose a unifying hypothesis for its effects on the maternal body. Even for lactation, a physiological state for which dimensional analysis using allometric equations yields some useful generalizations regarding its metabolic demands, species differences still exist (Blaxter, 1971; Hanwell & Peaker, 1977). Nonetheless there are many instances in which the changes in composition are broadly understandable in terms of the changing function of the maternal body and can be accepted as a general feature of reproduction. Thus, even if it were desirable to do so, it would be impossible to devise a nutritional regimen which would simultaneously permit normal reproduction and maintain maternal body composition unchanged throughout. Rather, the aim must be to produce balance in the composition of the body over the breeding cycle as a whole. There are many examples of the preceding principle in action. "he seasonal cycles in the food intake of the red deer and feral sheep, although in approximate synchrony with their nutrient needs are not exactly so and body fat stored before mating is lost in late pregnancy and early lactation (Mitchell et al. 1976: Milner & Gwynne, 1974). The grey seal provides an extreme example: in the few weeks following the birth of her pup she depends entirely on body reserves accumulated during pregnancy for the production of milk which contains over 50% fat and which promotes a daily live-weight gain in her pup of 1.5 kg (for review, see Widdowson, 1976, 1981). A similar phenomenon, albeit expressed in a much less spectacular way, occurs in a number of species, including humans, that tend to deposit fat in their bodies during pregnancy and lose it during lactation (Widdowson, 1976). Such examples portray the notion of an anticipatory role for the maternal body during reproduction. In reality they are responses to a sequence of.complex neuroendocrine and biochemical stimuli that follow on from conception and which are modified in their expression by the constraints imposed by the environment.
TL;DR: Two endo-(1→4)-β- d -xylanases (xylanase 1 and 2), which were constitutively synthesised by the fungus Trichoderma koningii, were purified to homogeneity on gel-filtration media and by isoelectric focusing.
TL;DR: Cross-bred does used in an experiment offered a diet of high nutrient density, milk yields and composition were similar for L and CPL does in early and mid-lactation, but in late lactation the milk output from CPL did declined rapidly, which was the period of maximal fetal growth rates.
Abstract: 1. In an experiment twenty-four cross-bred does were used, six in each of four physiological states: non-pregnant (NP), pregnant (P), lactating (L) or concurrently pregnant and lactating (CPL). They were offered a diet of high nutrient density (crude protein (nitrogen x 6.25) 272 g/kg dry matter (DM), metabolizable energy 15.5 MJ/kg DM) at one of two intakes on a scale based on metabolic body-weight (kg body-weight 0.75). The study lasted for 24 d and was divided into three consecutive 8 d periods: 'early', 'mid-' and 'late' pregnancy or lactation, or concurrent pregnancy and lactation. 2. Around the mid-point of each period the does were placed for 24 h in a gradient-layer calorimeter, and measurements of energy exchange were made. N balance was also measured throughout each period of the study. 3. Milk output in L and CPL does was measured by weighing the does immediately before and after suckling once each day. Milk samples were taken from a parallel group of does and the estimates of milk composition applied to the experimental group. 4. Milk yields and composition were similar for L and CPL does in early and mid-lactation, but in late lactation the milk output from CPL does declined rapidly. This was the period of maximal fetal growth rates. Energy and N retention increased in P and CPL does in late pregnancy. 5. Regression analysis was carried out to summarize the relations between metabolizable energy intake (MEI) and energy retention (ER; MEI-heat loss) in each physiological state. The equations were: NP: ER = 0.67 (SE 0.057) MEI-208, P: ER = 0.67 (SE 0.095) MEI-224, L: ER = 0.90 (SE 0.022) MEI-441, CPL: ER = 0.85 (SE 0.036) MEI-387, where all variables are expressed in kJ/kg body-weight 0.75 per d.
TL;DR: It is concluded that the lysosomal response serves to limit the absorption of nutritionally significant levels of these dietary toxins.
Abstract: The interactions between dietary kidney bean (Phaseolus vulgaris) lectins and the epithelial cells of the rat small intestine were investigated by immunogold electron microscopy. The results demonstrated that the lectins bind to the glycocalyx of duodenal and jejunal microvilli and that some of these dietary constituents are endocytosed into lysosomal pathways within both absorptive and secretory gut cells. It is concluded that the lysosomal response serves to limit the absorption of nutritionally significant levels of these dietary toxins.
TL;DR: Based on their ability to displace brominated phospholipids, relative binding constants to the ATPase of a series of phosphatidylcholines have been determined and are virtually unaffected by fatty acyl chain length or the presence of methyl branches.
TL;DR: Branched-chain volatile fatty acid production, which increased as the dilution rate of a glucose-limited chemostat decreased, seemed to be associated with maintenance rather than with growth.
Abstract: The amino acids in an acid hydrolysate of casein were catabolized more extensively by Megasphaera elsdenii than those in an enzymic hydrolysate Threonine and serine were most actively degraded, but no resultant increase in growth yield occurred Branched-chain volatile fatty acid production, which increased as the dilution rate of a glucose-limited chemostat decreased, seemed to be associated with maintenance rather than with growth
TL;DR: Delignified ryegrass cell walls were effectively hydrolysed by a mixture of endo-1,4-β-glucanase and xylanase, but the rate and extent of hydrolysis was greater when the cellobiohydrolase part of the cellulase system was also present.
TL;DR: Doe carcass composition changes revealed that fat was usually mobilized in early lactation and gained as lactation progressed independent of dietary treatment, and the protein content of the fat-free dry matter appeared to be relatively unaffected by the dietary treatments imposed.
Abstract: A study was made in rabbits on the effects of energy intake during pregnanoy on pup birth weight and survival, and on doe body composition and milk output in the ensuing lactation. In addition the experiment examined the effects of varying crudeprotein intakes during lactation on the rate of fat loss of does and the resultant energetic efficiency of milk production.Forty-seven multiparous cross-bred does were used. They were offered one of two diets in pregnancy, either diet HE (14·8 MJ digestible energy (DE)/kg D.M.) to appetite or diet LE (12·9 MJ DE/kg D.M.) at maintenance levels. After parturition seven does on each treatment were slaughtered and their body composition analysed (control groups). In lactation the remaining does were evenly allocated to receive either diet LE (195 g crude protein (CP)/kg D.M.) or diet HP (240 g CP/kg D.M.) to appetite. Litter sizes were standardized to six pups and litter growth rates were used as an indirect estimate of milk production. Does were then killed, at random, on day 9 or day 18 of lactation to give an estimate of changes in body composition as lactation progressed.Does offered diet HE during pregnancy had higher carcass fat levels at parturition than their counterparts offered diet LE (496 cf. 370 g/kg carcass D.M. respectively). Litter size was unaffected by dietary treatment during pregnancy but litter weights at birth were significantly greater in HE does (442 cf. 398 g respectively). Pup mortality at birth, however, was also much higher in these animals (28 cf. 9% respectively). Voluntary food intake in early lactation (day 1—9) was depressed by feeding diet HE during pregnanoy. Milk composition was affected by pregnancy diet, with does offered diet HE producing milk containing significantly higher fat levels (HE 123 g fat/kg milk cf. LE 105 g fat/kg milk).Doe carcass composition changes revealed that fat was usually mobilized in early lactation and gained as lactation progressed independent of dietary treatment. The protein content of the fat-free dry matter appeared to be relatively unaffected by the dietary treatments imposed. The data were used to derive an estimate of the partial efficiency of dietary energy utilization (fc) for milk output and maternal tissue gain. The line of best fit was described by the equation ER = 0·65 (±0·17) MEI-1–25, where ER = milk energy output + carcass energy change and MEI = metabolizable energy intake in MJ.
TL;DR: The preparations exhibited acceptable ADP:O ratios, high State-3 respiration rates, and respiratory control ratios in excess of 3 when succinate, beta-hydroxybutyrate, glutamate/malate and glutamine were test substrates.
TL;DR: This paper showed that the poor nutritional performance of rats fed raw soya-bean-containing diets appeared to be due to reduced apparent digestion and absorption of dietary protein, coupled to changes in systemic metabolism leading to a poor overall nitrogen balance.
Abstract: The poor nutritional performance of rats fed raw soya-bean-containing diets appeared to be due to reduced apparent digestion and absorption of dietary protein, coupled to changes in systemic metabolism leading to a poor overall nitrogen balance. Aqueous heat treatment greatly reduced but did not eliminate the antinutritional effect. Heat treatment with aqueous ethanol was more effective. The whey protein (pH 4.8 soluble extract) fraction contained the bulk of the trypsin inhibitor and haemagglutination activity and gave the poorest net protein utilisation value. However, an eight-fold increase in trypsin inhibitor content did not significantly effect apparent nitrogen digestibility. Therefore inhibition of gut proteolytic enzyme activity in vivo by soya bean trypsin inhibitors did not account fully for the poor nutritional performance. The problems elicited by soya bean are not transitory and thus there was a cumulative deterioration in overall performance for 16 weeks as a result of continuous exposure to soya bean.
TL;DR: Although a high concentration of copper (200 mg/kg) in the diet did not alter the percentage absorption and total-body retention of doses of 75SeO3(2)- by rats, after such treatment tissue 75Se distribution was changed and was lower total selenium in some tissues, it is unlikely that copper, cadmium, iron, molybdenum and manganese at normal dietary concentrations will have a major effect on seenium metabolism in the rat.
Abstract: The possible antagonistic effects of different dietary concentrations of copper (1.3-200 mg/kg), cadmium (1-5 mg/kg), iron (20-500 mg/kg), molybdenum (0.3-50 mg/kg) and manganese (0.2-200 mg/kg) on selenium utilization by the rat were studied by the measurement of the absorption and organ distribution of dietary selenium as (75Se)selenite and by effects on organ glutathione peroxidase (GSH-Px: EC 1.11.1.9) activity. Although a high concentration of copper (200 mg/kg) in the diet did not alter the percentage absorption and total-body retention of doses of 75SeO3(2)- by rats, after such treatment tissue 75Se distribution was changed and was lower total selenium in some tissues. After copper treatment (200 mg/kg diet) GSH-Px activity of liver, testis, kidney and whole blood was also lower. Dietary cadmium, iron, molybdenum and manganese at the concentrations investigated had no significant effects on selenium metabolism. Thus it is unlikely that copper, cadmium, iron, molybdenum and manganese at normal dietary concentrations will have a major effect on selenium metabolism in the rat, especially if adequate amounts of selenium are being consumed.