Zinc availability and digestive zinc solubility in piglets and broilers fed diets varying in their phytate contents, phytase activity and supplemented zinc source.
TL;DR: It is shown that dietary zinc was used more efficiently by broilers than by piglets, most probably due to the lower gizzard pH and its related higher zinc solubility, and that zinc supplementation, irrespective of zinc source, was successful in improving animal's zinc status.
Abstract: The study was conducted to evaluate the effects of dietary zinc addition (0 or 15 mg/kg of Zn as inorganic or organic zinc) to three maize–soybean meal basal diets varying in their native Zn, phytic P contents and phytase activity (expressed in kg of feed: P2 with 25 mg Zn and 1.3 g phytic P, P1 with 38 mg Zn and 2.3 g phytic P or P1/ENZ being P1 including 500 units (FTU) of microbial phytase per kg) in two monogastric species (piglets, broilers). Measured parameters were growth performance, zinc status (plasma, and bone zinc) and soluble zinc in digesta (stomach, gizzard and intestine). The nine experimental diets were fed for 20 days either to weaned piglets (six replicates per treatment) or to 1-day-old broilers (10 replicates per treatment). Animal performance was not affected by dietary treatments ( P . 0.05) except that all P2 diets improved body weight gain and feed conversion ratio in piglets ( P , 0.05). Piglets fed P2 diets had a better Zn status than those fed P1 diets ( P , 0.05). In both species, Zn status was improved with supplemental Zn ( P , 0.05), irrespective of Zn source. Phytase supplementation improved piglet Zn status to a higher extent than adding dietary Zn, whereas in broilers, phytase was less efficient than supplemental Zn. Digestive Zn concentrations reflected the quantity of ingested Zn. Soluble Zn (mg/kg dry matter) and Zn solubility (% of total Zn content) were highest in gizzard contents, which also presented lower pH values than stomach or intestines. The intestinal Zn solubility was higher in piglet fed organic Zn than those fed inorganic Zn ( P , 0.01). Phytase increased soluble Zn in piglet stomach ( P , 0.001) and intestine ( P 5 0.1), but not in broiler gizzard and intestinal contents. These results demonstrate (i) that dietary zinc was used more efficiently by broilers than by piglets, most probably due to the lower gizzard pH and its related higher zinc solubility; (ii) that zinc supplementation, irrespective of zinc source, was successful in improving animal’s zinc status; and (iii) suggest that supplemented Zn availability was independent from the diet formulation. Finally, the present data confirm that phytase was efficient in increasing digestive soluble Zn and improving zinc status in piglets. However, the magnitude of these effects was lower in broilers probably due to the naturally higher Zn availability in poultry than in swine.
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TL;DR: The future of enzymes in nonruminant animal production is promising and will likely include an understanding of the role of enzyme supplementation in promoting health as well as how enzymes may modulate gene functions.
Abstract: Diets fed to nonruminant animals are composed mainly of feed ingredients of plant origin. A variety of antinutritional factors such as phytin, nonstarch polysaccharides, and protease inhibitors may be present in these feed ingredients, which could limit nutrients that may be utilized by animals fed such diets. The primary nutrient utilization-limiting effect of phytin arises from the binding of 6 phosphate groups, thus making the P unavailable to the animal. The negative charges allow for formation of insoluble phytin-metal complexes with many divalent cations. Furthermore, phytin and protein can form binary complexes through electrostatic links of its charged phosphate groups with either the free amino group on AA on proteins or via formation of ternary complexes of phytin, Ca(2+), and protein. The form and extent of de novo formation of binary and ternary complexes of phytin and protein are likely to be important variables that influence the effectiveness of nutrient hydrolysis in plant-based diets. Nonstarch polysacharides reduce effective energy and nutrient utilization by nonruminant animals because of a lack of the enzymes needed for breaking down the complex cell wall structure that encapsulate other nutrients. Enzymes are used in nonruminant animal production to promote growth and efficiency of nutrient utilization and reduce nutrient excretion. The enzymes used include those that target phytin and nonstarch polysaccharides. Phytase improves growth and enhances P utilization, but positive effects on other nutrients are not always observed. Nonstarch polysaccharide-hydrolyzing enzymes are less consistent in their effects on growth and nutrient utilization, although they show promise and it is imperative to closely match both types and amounts of nonstarch polysaccharides with appropriate enzyme for beneficial effects. When used together with phytase, nonstarch polysaccharide-hydrolyzing enzymes may increase the accessibility of phytase to phytin encapsulated in cell walls. The future of enzymes in nonruminant animal production is promising and will likely include an understanding of the role of enzyme supplementation in promoting health as well as how enzymes may modulate gene functions. This review is an attempt to summarize current thinking in this area, provide some clarity in nomenclature and mechanisms, and suggest opportunities for expanded exploitation of this unique biotechnology.
447 citations
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TL;DR: This review article addresses the effect of unconventionally high doses of phytase on nutrient requirement and suggests mechanisms by which they may be explained.
Abstract: Phytases have been used commercially since the early 1990s and have been the focus of considerable and sustained research for many decades. Despite this heroic effort there are still areas of persi...
156 citations
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TL;DR: In a practical European broiler diet, the organic Availa-Zn had a higher bioavailability than inorganic zinc sulfate, as indicated by the slope ratio of the linear response curves for both zinc sources, using tibia zinc content as a response parameter.
Abstract: The objective of the current study was to determine the bioavailability of an organic zinc source (Availa-Zn) compared with zinc sulfate in a European-type broiler diet. A total of 480 one-day-old male Ross 308 broilers were housed in 48 digestibility cages (10 birds per cage), being randomly divided over 9 treatments. At d 3, the number of birds was standardized to 8. Birds were fed a basal wheat-maize-soya diet (containing 33.5 mg of Zn/kg) with different supplementation levels of zinc (reference zinc source: inorganic zinc sulfate: 0, 5, 10, 15, 20, and 40 mg of Zn/kg of feed; test zinc source: Availa-Zn: 0, 5, 10, 15 mg of Zn/kg of feed). Production performance and tibia zinc content were measured. There were no differences in production performance between the different zinc sources when fed to broilers until 21 d of age. Tibia zinc content was increased linearly with the dietary zinc content up to 20 mg/kg zinc sulfate. The relative biological value of organic zinc was 1.64 compared with zinc sulfate as a reference zinc source (1.00), as indicated by the slope ratio of the linear response curves for both zinc sources, using tibia zinc content as a response parameter. In a practical European broiler diet, the organic Availa-Zn had a higher bioavailability than inorganic zinc sulfate.
61 citations
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TL;DR: The discrepancy between the mineral content and the amount of minerals that can be released and absorbed from plant-based foods during human digestion can be attributed to several inherent factors such as the presence of mineral antinutrients, polyphenols and dietary fiber and physical barriers.
Abstract: Plant-based foods gain more importance since they play a key role in sustainable, low-meat and healthy diets. In developing countries, these food products, especially legumes and cereals, are important staple foods. Nevertheless, the question arises on how efficient they are to deliver minerals and if it is useful to encourage their consumption to reduce the prevalence of mineral deficiencies? This review paper focuses on the discrepancy between the mineral content and the amount of minerals that can be released and absorbed from plant-based foods during human digestion which can be attributed to several inherent factors such as the presence of mineral antinutrients (phytic acid, polyphenols and dietary fiber) and physical barriers (surrounding macronutrients and cell wall). Further, this review paper summarizes the effects of different processing techniques (milling, soaking, dehulling, fermentation, germination and thermal processing) on mineral bioaccessibility and bioavailability of plant-based foods. The positive impact of these techniques mostly relies on the fact that antinutrients levels are reduced due to removal of fractions rich in antinutrients and/or due to their leaching into the processing liquid. Although processing can have a positive effect, it also can induce leaching out of minerals and a reduced mineral bioaccessibility and bioavailability.
46 citations
References
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10 May 2004
TL;DR: This book presents the chemical composition and nutritive values of domestic animals and fishes in tabular form and the feed materials included are Other CABI sites.
Abstract: This book presents the chemical composition and nutritive values of domestic animals and fishes in tabular form. The feed materials included in this work are Other CABI sites
671 citations
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TL;DR: A simple and rapid method is described for determining the enzymatic activity of microbial phytase based on the determination of inorganic orthophosphate released on hydrolysis of sodium phytate at pH 5.5.
Abstract: A simple and rapid method is described for determining the enzymatic activity of microbial phytase. The method is based on the determination of inorganic orthophosphate released on hydrolysis of sodium phytate at pH 5.5.
452 citations
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TL;DR: The bioavailability of zinc-methionine (ZnMET) was compared to that of feed-grade ZnSO4.H2O using three different diets: purified (crystalline amino acid [AA]), semipurified (soy isolate), and complex (corn-soybean [C-SBM]) diet to indicate differences in Zn bioavailability.
Abstract: The bioavailability of zinc-methionine (ZnMET) was compared to that of feed-grade ZnSO4.H2O using three different diets: purified (crystalline amino acid [AA]), semipurified (soy isolate), and complex (corn-soybean [C-SBM]) diet. With the Zn-deficient purified or semipurified diet, weight gain and tibia Zn responded linearly to both ZnSO4.H2O and ZnMET supplementation. Common-intercept, multiple linear regression indicated differences in Zn bioavailability between ZnMET and ZnSO4.H2O for both diets as indicated by bone Zn. With the ZnSO4.H2O standard set at 100%, bioavailability of Zn from ZnMET was 117% (P less than .05) in the AA diet and 177% (P less than .01) in the soy isolate diet. The ZnMET was also compared to ZnSO4.H2O in a C-SBM diet containing 117 mg of Zn/kg. When high levels of Zn were added to this diet (0, 250, 500, and 750 mg/kg of supplemental Zn), consistent tissue Zn responses did not occur beyond the first increment. Addition of lower levels of supplemental Zn (0, 5, 10, 20, 30, 40 and 50 mg/kg) to a Zn-unsupplemented C-SBM basal diet (45 mg/kg of Zn), however, resulted in a broken-line, two-slope response in tibia Zn for both ZnMET and ZnSO4.H2O. Inflection points occurred at 60 and 54 mg of Zn/kg of diet for ZnSO4.H2O and ZnMET, respectively. The ratio of slopes (ZnMET:ZnSO4.H2O) below the inflection points was 206% (P less than .01), indicating that Zn was considerably more bioavailable in ZnMET than in ZnSO4.H2O for chicks consuming C-SBM diets. When feed-grade ZnO was compared to feed-grade ZnSO4.H2O in chicks consuming C-SBM diets, bone Zn slopes below the respective inflection points indicated that Zn was 61% bioavailable in ZnO relative to ZnSO4.H2O.
435 citations
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