Effect of phytase inclusion and calcium/phosphorus ratio on the performance and nutrient retention of grower–finisher pigs fed barley/wheat/soya bean meal‐based diets

Two experiments were conducted to evaluate the effects of phosphorus (P) level and calcium (Ca)/total P (tP) ratio on the efficacy of microbial phytase. Experiment 1 examined the effects of P concentration and microbial phytase inclusion on mineral excretion and pig performance, while experiment 2 examined the effects of Ca/tP ratio and microbial phytase inclusion on mineral excretion and pig performance. In experiment 1, nutrient and mineral digestibility (n = 4) and growth performance (n = 12) were determined in pigs individually fed diets containing (T1) 5.5 g kg^?1 tP, 2.3 g kg^?1 available P (aP) and 8.0 g kg^?1 Ca, (T2) 5.5 g kg^?1 tP, 2.3 g kg^?1 aP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 Peniophora lycii phytase, (T3) 4.3 g kg^?1 tP, 1.4 g kg^?1 aP and 8.0 g kg^?1 Ca and (T4) 4.3 g kg^?1 tP, 1.4 g kg^?1 aP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase. In experiment 2, nutrient and mineral digestibility (n = 4) and growth performance (n = 12) were determined in pigs individually fed diets containing (TT1) 4.3 g kg^?1 tP and 8.0 g kg^?1 Ca, (TT2) 4.3 g kg^?1 tP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase, (TT3) 4.3 g kg^?1 tP and 5.0 g kg^?1 Ca and (TT4) 4.3 g kg^?1 tP, 5.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase. All diets were formulated, using standard feeding values for the ingredients, to have similar concentrations of digestible energy (DE) and lysine. In experiment 1, pigs offered the low‐P diets had significantly lower P intake (P < 0.001), faecal P excretion (P < 0.05), Ca intake (P < 0.05) and faecal Ca excretion (P < 0.05) compared with pigs given the adequate‐P diets. These pigs also had significantly lower daily gain (P < 0.01), feed intake (P < 0.05) and feed conversion ratio (FCR) (P < 0.05). The inclusion of phytase in both the adequate‐ and low‐P diets increased the digestibility of energy (P < 0.05) and Ca (P < 0.01) but had no effect on pig performance. In experiment 2, lowering the Ca/tP ratio from 1.85:1 to 1.15:1 increased the DE content of the diet (P < 0.05). The inclusion of phytase increased (P < 0.05) the digestibility of protein (0.874 versus 0.840, SEM 0.009) and Ca (0.427 versus 0.380, SEM 0.019) as well as the DE content of the diet (14.47 versus 14.26 MJ kg^?1, SEM 0.073). There was a significant ratio × phytase interaction (P < 0.5) for P digestibility. Microbial phytase significantly increased P digestibility when added to the 1.15:1 ratio diet but had no effect when added to the 1.85:1 ratio diet. The inclusion of microbial phytase increased feed intake (2.16 versus 2.00 kg day^?1, SEM 0.05; P < 0.05) and weight gain (0.893 versus 0.818 kg day^?1, SEM 0.022; P < 0.05). Lowering the Ca/tP ratio resulted in a significant improvement in FCR (2.32 versus 2.40 kg kg^?1, SEM 0.03; P < 0.05). In conclusion, the beneficial effects of microbial phytase supplementation of pig diets are adversely affected by a wide Ca/tP ratio. © 2002 Society of Chemical Industry     

Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Phytic acid present in the raw materials can complex with many compounds and therefore limit their availability to the yeast during the alcoholic fermentation process. An effective utilization of biogenic compounds bound in phytates requires a detailed analysis of the raw materials for their phytic acid content. The aim of this study was to characterize the major technological parameters for selected raw materials used in the distilling industry (maize, rye, wheat and triticale grain) and to determine the phytic acid content and the IP6/total phosphorus ratio. The phytic acid hydrolysis rate during the mashing process, with the use of microbial phytases, was analysed. The highest phytic acid concentrations (2.30 ± 0.20 mg/g dry matter) and the highest IP6/total P (80.42 ± 6.99%) were observed in the maize grain samples. Therefore, further studies on the phytic acid hydrolysis rate with the use of various phytases were conducted for the maize grain. The highest hydrolytic activity was observed for the Phytase 10000L preparation. This was the preparation that hydrolysed the phytic acid completely in up to 90 min. The application of a highly effective phytase, in ethanol production from maize grain, could lead to a more effective utilization of the biogenic compounds during the fermentation process. Copyright © 2015 The Institute of Brewing & Distilling     

The degradation of phytate by microbial and wheat phytases is dependent on the phytate matrix and the phytase origin

BACKGROUND: Phytases increase utilization of phytate phosphorus in feed. Since wheat is rich in endogenous phytase activity it was examined whether wheat phytases could improve phytate degradation compared to microbial phytases. Moreover, it was investigated whether enzymatic degradation of phytate is influenced by the matrix surrounding it. Phytate degradation was defined as the decrease in the sum of InsP₆ + InsP₅. RESULTS: Endogenous wheat phytase effectively degraded wheat InsP₆ + InsP₅ at pH 4 and pH 5, while this was not true for a recombinant wheat phytase or phytase extracted from wheat bran. Only microbial phytases were able to degrade InsP₆ + InsP₅ in the entire pH range from 3 to 5, which is relevant for feed applications. A microbial phytase was efficient towards InsP₆ + InsP₅ in different phytate samples, whereas the ability to degrade InsP₆ + InsP₅ in the different phytate samples ranged from 12% to 70% for the recombinant wheat phytase. CONCLUSION: Wheat phytase appeared to have an interesting potential. However, the wheat phytases studied could not improve phytate degradation compared to microbial phytases. The ability to degrade phytate in different phytate samples varied greatly for some phytases, indicating that phytase efficacy may be affected by the phytate matrix. Copyright © 2011 Society of Chemical Industry     

Effects and biotransformation of the mycotoxin deoxynivalenol in growing pigs fed with naturally contaminated pelleted grains with and without the addition of Coriobacteriaceum DSM 11798

Deoxynivalenol (DON) is one of the most prevalent Fusarium mycotoxins in grain and can cause economic losses in pig farming due to reduced feed consumption and lower weight gains. Biodetoxification of mycotoxins using bacterial strains has been a focus of research for many years. However, only a few in vivo studies have been conducted on the effectiveness of microbial detoxification of fusariotoxins. This study was therefore aimed at investigating the effect of a feed additive containing the bacterial strain Coriobacteriaceum DSM 11798 (the active ingredient in Biomin® BBSH 797) on growth performance and blood parameters, as well as uptake and metabolism of DON, in growing pigs. Forty-eight crossbred (Landrace-Yorkshire/Duroc-Duroc) weaning pigs were fed with pelleted feed made from naturally contaminated oats, with DON at four concentration levels: (1) control diet (DON < 0.2 mg kg^?1), (2) low-contaminated diet (DON = 0.92 mg kg^?1), (3) medium-contaminated diet (DON = 2.2 mg kg^?1) and (4) high-contaminated diet (DON = 5.0 mg kg^?1) and equivalent diets containing DSM 11798 as feed additive. During the first 7 days of exposure, pigs in the highest-dose group showed a 20–28% reduction in feed intake and a 24–34% reduction in weight gain compared with pigs in the control and low-dose groups. These differences were levelled out by study completion. Towards the end of the experiment, dose-dependent reductions in serum albumin, globulin and total serum protein were noted in the groups fed with DON-contaminated feed compared with the controls. The addition of DSM 11798 had no effect on the DON-related clinical effects or on the plasma concentrations of DON. The ineffectiveness of the feed additive in the present study could be a consequence of its use in pelleted feed, which might have hindered its rapid release, accessibility or detoxification efficiency in the pig’s gastrointestinal tract.     

Performance and carcass characteristics of growing pigs and broilers fed diets containing micronised barley,ground barley,wheat and maize

Two swine starter/grower/finisher trials utilising 216 24‐day‐old pigs and one 40‐day broiler growth trial utilising 1920 1‐day‐old chicks were conducted to determine the influence of dietary micronised dehulled barley (MDB) as a replacement for hulled barley (HB), wheat (W) and maize (M) on live performance, carcass and meat measurements, organ weights (swine), plasma urea nitrogen (PUN) level (swine) and intestinal digesta viscosity (broilers). Dehulling and micronising the barley reduced crude protein by 20%, neutral detergent fibre by 17% and amino acids by varying amounts. Replacing M or W with MDB in swine diets had no effect (P > 0.05) on any measured parameter, with the exception of decreased PUN (P = 0.03) when MDB replaced 100% of W. Broilers fed W, M or HB generally had similar live performance, carcass traits and digesta viscosity, with the exception of reduced (P < 0.05) average daily gain and average daily feed intake for HB during the first 20 days of the trial. However, broilers fed MDB had slightly reduced (P = 0.05) live performance during each phase of the trial and greatly increased (P = 0.01) digesta viscosity. Addition of a commercial enzyme product to the diets reversed the reduced performance and increased the digesta viscosity of the MDB diet, but generally had no influence in the W, M and HB diets. These results suggest that MDB can be utilised in swine diets without affecting performance, but that reduced performance may result from its use in broiler diets. © 2001 Society of Chemical Industry     

Response of pancreatic secretions to feeding diets with low and high levels of soybean trypsin inhibitors in growing pigs

Studies were carried out to determine the effect of soybean trypsin inhibitors (SBTI) on exocrine pancreatic secretions in growing pigs. Six barrows with an average initial body weight (BW) of 27·1±1·4 kg were fitted with permanent pancreatic re-entrant cannulas and fed two diets according to a crossover design. Two maize starch-based diets were formulated to contain 200 g kg⁻¹ crude protein from either Nutrisoy (food grade defatted soy flour) or autoclaved Nutrisoy. The concentrations of SBTI in Nutrisoy and autoclaved Nutrisoy diets were 13·4 and 3·0 g kg⁻¹, respectively. The experiment consisted of two periods of 9 days each. The average BW at the start of the first and second experimental periods was 33·5±2·7 and 37·2±3·7 kg, respectively. The average BW at the conclusion of the experiment was 41·8±3·9 kg. The volume of pancreatic secretion was higher (P<0·01) when the Nutrisoy, as opposed to the autoclaved Nutrisoy diet was fed (3804 vs 2634 ml (24 h)⁻¹). The concen-tration of nitrogen and protein and specific activities (units litre⁻¹) of amylase, chymotrypsin and trypsin were lower (P<0·05) in pancreatic juice of pigs fed the Nutrisoy diet. There were no differences (P>0·05) in the total secretions of nitrogen (g (24 h)⁻¹) and total activities (units (24 h)⁻¹) of amylase, lipase, chymotrypsin and trypsin in pancreatic juice of pigs fed the Nutrisoy and autoclaved Nutrisoy diets. However, the total secretion of protein was slightly higher (25·7 vs 22·8 g (24 h)⁻¹; P<0·05) in pancreatic juice of pigs fed the autoclaved Nutrisoy diet, which corresponded with the increase in the secretion of protein-bound amino acids. There was also an increase in the total secretion of free amino acids in pancreatic juice. These studies show no effect of SBTI on the total enzyme activities in pancreatic juice of growing pigs. © 1998 SCI.     

Influence of lipase and/or emulsifier addition on the ileal and faecal nutrient digestibility in growing pigs fed diets containing 4% animal fat

Information on the addition of lipase and/or emulsifiers to less digestible or saturated fat sources, such as tallow or other animal fats, used in swine feeding is very limited. Therefore, in a 4 × 4 Latin square design, the effects of adding lipase (0.05% L5, microbial source) and/or an emulsifier (0.3% Lysoforte) on the apparent ileal (AID) and faecal (AFD) digestibility of the main nutrients and fatty acids in particular were studied with four ileal‐cannulated growing pigs (female, initial live weight 20 kg) fed diets containing barley/soybean meal supplemented with 4% animal fat. The fat source contained 35% saturated (S) and 65% unsaturated (U) fatty acids. All diets were free of antibacterial substances (antibiotics, copper sulphate or zinc oxide beyond requirements), in order to avoid interactions between the parameters studied and the gut flora. Lipase addition did not affect the AID or AFD of fat. However, the digestibility of minor fatty acids (C6:0, C14:0) was significantly improved by lipase at both ileal and faecal level. On the other hand, lipase supplementation (P < 0.05) improved the AID of dry matter (DM) and energy as well as the AFD of DM, organic matter (OM), crude protein (CP), ash and energy. Addition of an emulsifier did not have any significant influence on the AID or AFD of fat, while the AID values of DM, OM, CP and energy as well as the AFD values of DM, OM, CP and ash were significantly (P < 0.05) improved. Adding lipase in combination with an emulsifier to the diets decreased (P < 0.05) the AID and AFD of fat, with minor effects on the AID and AFD of the non‐fat components of the diet. The lack of improvement in the digestion of fat by exogenous lipase and/or emulsifier may be related to the rather high U/S ratio (0.65:0.35) of the animal fat source used and to the mode of incorporation of the emulsifier (no pre‐dispersion in the fat source). Furthermore, during the trial the diets, stored at room temperature, showed a steady increase in their content of free fatty acids (to more than 700 g kg^?1 fat), due to endogenous lipase activity, leaving less room for upgrading the digestion of animal fat by exogenous lipase and/or emulsifier. Copyright © 2004 Society of Chemical Industry     

Energy and nutrient digestibilities in wheat dried distillers' grains with solubles fed to growing pigs

The aim of this study was to characterize the nutritional profile and to determine the digestibilities of nutrients in wheat‐based dried distillers' grains with solubles (DDGS) fed to growing pigs. Six ileal cannulated barrows individually housed in metabolism crates were fed experimental diets which consisted of a basal wheat‐based diet or the basal diet with wheat replaced by 400 g kg^?1 mixed wheat or winter wheat DDGS in a replicated 3 × 3 Latin square design. Ileal digesta and fecal samples were collected for determining apparent ileal (AID) and apparent total tract digestibilities (ATTD), respectively. The contents of proximate components and amino acids in DDGS were about three times higher than in wheat. The AID and ATTD of dry matter, nitrogen and energy were lower (P < 0.05) in DDGS compared with wheat. The DDGS samples had lower (P < 0.05) AID of amino acids compared with wheat; average values for lysine, threonine and isoleucine in DDGS were 43.8, 62.9 and 68.0%, respectively. The ileal and fecal digestible energy content in DDGS averaged 9.7 ± 1.18 and 13.5 ± 0.61 MJ kg^?1, respectively. Respective values for wheat were 13.3 ± 0.52 and 14.6 ± 0.22 MJ kg^?1 and both were higher (P < 0.05) than in DDGS. Copyright © 2005 Society of Chemical Industry     

Response of nutrient digestibilities to feeding diets with low and high levels of soybean trypsin inhibitors in growing pigs

Studies were carried out to determine the effect of dietary soybean trypsin inhibitor (SBTI) content on nutrient and energy digestibilities in growing pigs. Six barrows, average initial body weight (BW) 47·8±4·0 kg, were fitted with a simple T-cannula at the distal ileum and fed two diets according to a crossover design. Two maize starch-based diets were formulated to contain 200 g crude protein (CP) kg⁻¹ from either Nutrisoy (a food-grade defatted soy flour) or autoclaved Nutrisoy. The contents of SBTI in the Nutrisoy and autoclaved Nutrisoy diets were 13·4 and 3·0 g kg⁻¹, respectively. The experiment consisted of two periods of 12 days each. The average BW at the start of the first and second experimental periods were 53·3±3·7 and 61·0±5·1 kg, respectively. The average BW at the conclusion of the experiment was 71·8±7·6 kg. The ileal digestibilities of dry matter (DM), organic (OM), energy, CP and all amino acids measured were higher (P<0·01) in pigs fed the autoclaved Nutrisoy diet. The energy digestibility increased from 66·0 to 77·9%, and the CP digestibility increased from 37·4 to 77·1%. The increases in ileal digestibilities of the indispensable amino acids ranged from 27·0 (methionine) to 49·2 (leucine) percentage units. The increases in ileal digestibilities of the dispensable amino acids ranged from 30·2 (aspartic acid) to 50·8 (tyrosine) percentage units. The faecal digestibilities of all criteria measured were also higher (P<0·01) in pigs fed the autoclaved Nutrisoy diet. Furthermore, there was a greater (P<0·01) net disappearance (g kg⁻¹ DM intake) of DM, OM, CP, energy and all amino acids in the large intestine of pigs fed the Nutrisoy diet. In conclusion, feeding diets containing high levels of SBTI decreased both ileal and faecal digestibilities of all criteria measured. The formation of SBTI-enzyme complexes is likely to be responsible for the reduction in protein digestion and amino acid absorption. © 1998 SCI.     

Monitoring the stepwise phytate degradation in the upper gastrointestinal tract of pigs

The degradation and formation of inositol phosphates as affected by microbial phytase and gastrointestinal enzyme activities during the passage of phytate through the stomach and small intestine were studied in two experiments with four barrows and three collection periods. The degradation and formation of inositol phosphates were measured at the duodenal and ileal sites using Cr‐NDR, TiO₂ and Co‐EDTA as indigestible markers. In experiment 1, the effect of graded doses of Aspergillus niger phytase (0, 150 and 900 FTU Natuphos^® kg^?1), added to a maize–soybean meal‐based diet with very low intrinsic phytase activity on the degradation of phytate and the formation of inositol phosphates during digestion in the stomach and small intestine was investigated. In experiment 2, three different mixtures of inositol phosphates, produced by Aspergillus niger phytase, containing mainly high, intermediate and low phosphorylated inositol phosphates, were added to the same maize–soybean meal‐based diet as used in experiment I. The fate of the inositol phosphates during digestion in the stomach and small intestine was studied. Experiment 1 showed that the extent of phytate degradation was dependent of the graded dietary phytase activities. At high phytase activity (900 FTU kg^?1 of diet), strong phytate degradation occurred and the once hydrolysed phytate was rapidly dephosphorylated to lower inositol phosphates (mainly inositol di‐ and triphosphates). Intermediate inositol phosphates, such as inositol tetraphosphates, were quantitatively unimportant in duodenal and ileal digesta. At a phytase activity of 150 FTU kg^?1 of diet, a broader spectrum of intermediate inositol phosphates was determined, which was probably due to a slower breakdown of phytate. Experiment 2 showed as a predominant result that lower inositol phosphates such InsP₄ and InsP₃ were degraded, whereas InsP₂ accumulated in the duodenal and ileal digesta. No substantial disappearance of phytate from the stomach and small intestine was found when high concentrations of soluble phytate were added to the diet, which indicates that no substantial phytate absorption occurs in the upper part of the pig gut. Copyright © 2005 Society of Chemical Industry     

Effect of feeding different diets on the exocrine pancreatic secretion of nitrogen,amino acids and enzymes in growing pigs

Five barrows were fitted with permanent pancreatic re-entrant cannulas to determine the influence of diet on exocrine pancreatic secretions in the weight range from 40 to 65 kg. The pigs were fed four diets. Diets 1 and 2 were based on corn starch and contained 18.6 and 16.9 % crude protein (dry matter basis) from soybean meal and canola meal, respectively. Diets 3 and 4 contained 93.9 % wheat and barley, respectively. In the same order, the crude protein contents (dry matter basis) of these diets were 14.4 and 11.2%, respectively. The experiment was carried out according to 4 × 4 Latin square design. Each experimental period comprised 12 days. Following an adaptation period of 8 days, pancreatic juice was collected from 08:00 on day 9 to 08:00 h on day 10 and from 08:00 on day 11 to 08:00 h on day 12. The pigs were fed twice daily, at 08:00 and 20:00 h, 800 g each meal. Despite large differences, up to 23%, between the overall mean values of the parameters that were measured there was no effect (P > 0.05) of diet on the volume of secretion of pancreatic juice, the pH and the secretion of total and TCA-precipitable nitrogen. Due to the high level of within-study variation there was also no effect (P > 0.05) of diet on the secretion of amino acids and the total activity of trypsin, chymotrypsin, α-amylase and lipase in pancreatic juice.     

Utilization of phosphorus in lactating cows fed varying amounts of phosphorus and forage

The objective of this study was to determine the effect of dietary forage proportion and P content on fecal P excretion. Four dietary treatments were formed in a 2 x 2 factorial arrangement. The P content was 0.33 or 0.42%, and the forage proportion was 48 or 58% on a dry matter (DM) basis. The neutral detergent fiber content was 27 and 30% for the low and high forage diets, respectively. The P amount was varied by using monosodium phosphate, and the forage amount by changing the proportions of alfalfa silage and corn. The diets were fed to 44 midlactation Holsteins for 14 wk. Fecal P excretion was estimated using Cr marker and grab sampling. Dietary P content did not affect DM intake, milk yield, or milk composition. The P intake averaged 74 and 96 g/d and fecal P averaged 0.69 and 0.92% (DM basis) or 49 and 65 g/d for the low and high P diets, respectively. Thus, reducing dietary P from 0.42 to 0.33% resulted in approximately 25% less estimated fecal P excretion. Increasing dietary forage reduced milk yield (34.0 vs. 36.5 kg/d), but increased milk fat content (3.66 vs. 3.25%). Estimated apparent digestibility of P tended to decrease (31.1 vs. 36.6%) when the forage proportion increased, but most of the change occurred when the diets contained the low amount of P. Overall, the effect of forage proportion on estimated fecal P excretion was small when diets contained 48 or 58% forage, varied by alfalfa silage. Phosphorus intake has a much larger impact on fecal P excretion than forage proportion, and it does not seem necessary to adjust the dietary P content according to the forage proportion to provide the same amount of absorbed P.     

Effects of including raw or extruded field peas (Pisum sativum L.) in diets fed to weanling pigs

BACKGROUND: There is limited information about the response to field peas fed to weanling pigs. Two experiments were therefore conducted to investigate effects of including increasing levels of field peas in weanling pig diets. RESULTS: In Experiment 1, a reduction (linear, P < 0.05) in average daily gain (551, 574, 541, 548, 512 and 533 g d^?1) was observed in response to increasing levels of raw field peas (0, 120, 240, 360, 480 and 600 g kg^?1) in diets fed from day 14 to 42 post weaning. In Experiment 2, the inclusion of raw field peas (0, 245 or 490 g kg^?1) in the diets reduced (linear, P < 0.05) feed intake from day 14 to 39 post weaning, but average daily gain and gain:feed were unaffected by the use of raw field peas. The response to extruded field peas was not different from that to raw field peas. CONCLUSION: Up to 360 g kg^?1 raw field peas may be included in nursery diets without negatively influencing pig growth performance provided that diets are balanced for indispensable amino acids. Results from this work do not support any advantage of extruding the field peas. Copyright © 2010 Society of Chemical Industry     

Effect of grain source and exogenous phytase on phosphorus digestibility in dairy cows

Two experiments were conducted to determine P digestibility in lactating dairy cows fed corn or barley as grain sources. The first experiment utilized a replicated incomplete 5 × 4 Latin square design with 8 lactating Holstein cows fed diets containing either corn alone or corn in combination with one of 4 barley varieties that differed in chemical composition. Total tract digestibility of P ranged from 11 to 29% for diets containing the barley varieties and was approximately 35% for the corn diet. A second experiment compared P digestibility in cows fed diets containing corn or barley when exogenous phytase was added to the diets. Lactating Holstein cows (n = 16) were arranged in 4 replications of a Latin square with 2 grains (barley or corn), fed separately or with added exogenous phytase (427 phytase units/kg of total mixed ration and 4 periods of 21 d. Phytate P comprised about 50% of the total P (0.46% P) in the total mixed ration. The concentration of serum inorganic P was higher in cows fed diets with exogenous phytase (5.8 vs. 6.5 mg/dL in cows fed barley diets and 5.5 vs 6.0 mg/dL in cows fed corn diets). Using acid detergent lignin as an internal marker, hydrolysis of phytate P was increased by the exogenous phytase, and total P digestibility tended to be increased. In contrast to Experiment 1, in Experiment 2 there was no effect of grain source on P digestibility and total fecal P. Dry matter intake and efficiency of milk production were not affected by exogenous phytase or grain type. Although phytase activity occurs in the rumen, physical properties of the diet and ruminal passage rates may prevent total hydrolysis of phytate in the rumen of lactating cows. Thus, exogenous dietary phytase might improve P digestibility in dairy cows in some dietary situations.     

半胱胺和酵母铬对生长猪饲粮养分消化代谢的影响

采用全收粪(尿)法,进行消化代谢试验,研究生长猪饲粮中分别或同时添加半胱胺和酵母铬对饲粮养分的消化利用率影响。结果表明:生长猪饲粮中分别或同时添加半胱胺和酵母铬在一定程度上改善了饲粮干物质、无氮浸出物、粗蛋白质、总能、粗脂肪、粗纤维、钙和总磷等养分的表观消化吸收率,提高了氮的沉积率和表观生物学价值(P>0.05);酵母铬和半胱胺二者具有一定的协同作用。