Apparent metabolisable energy and digestibility of shea (Vitellaria paradoxa) fat, cocoa (Theobroma cacao) fat and soybean oil in broiler chicks

1. The objective of this experiment was to determine and compare the apparent lipid digestibility coefficient and apparent metabolisable energy (AME) value of shea nut (Vitellaria paradoxa, Gaertn.) fat in broiler chickens with that of soybean oil and cocoa fat. 2. One hundred and sixty 13-d-old male broiler chicks were used in a randomised complete block design. The fats were added at 30, 60 and 90 g/kg to a basal diet. A tenth dietary treatment was the basal feed with no added fats or oils. The birds were fed on the diets for 8 d and all droppings were collected for the final 4 d. 3. The mean coefficient of apparent lipid digestibility for shea fat (0.58) was similar to that of cocoa fat (0.54) but lower than that of soybean oil (0.95). There was evidence of a lipid x concentration interaction with the 90 g/kg shea fat diet having low lipid digestibility (0.43). 4. There was an interaction between the effects of dietary lipid concentration and test lipid on AME but, at dietary levels of 60 g/kg and below, the AME of shea fat (22.0 MJ/kg DM) and cocoa fat (26.4 MJ/kg DM) was significantly lower than that of soybean oil (39.8 MJ/kg DM).     

Influence of age, chemical composition and rate of inclusion on the apparent metabolisable energy of fats fed to broiler chicks

1. Vegetable oil (VO) and tallow (T) were evaluated at rates of 25, 50, 75, 100 and 125g/kg in a basal diet with broiler chicks aged 1.5, 3.5, 5.5 and 7.5 weeks of age using a total collection period of 72 h. 2. Apparent metabolisable energy, corrected to zero nitrogen retention (AMEN, MJ/kg) and apparent fat availability (AFA, g/kg) of the experimental diets were employed to estimate the dietary energy values of fats, by linear and quadratic regression. 3. AME of fats, determined from AFA, had smaller standard errors than those determined from AMEN. 4. There was a marked increase in the AME of fats from 1.5 to 3.5 weeks of age; thereafter, the improvement was less pronounced. 5. Rate of improvement in fat AME with age was greater with T than VO.     

脂肪生物有效能值的测定

本试验方法测定的有效能值不同于传统的代谢能值,是基于生长反应来测定的,实为生长效应能值。试验利用１～３和４～６周龄的肉仔鸡测定不同脂肪来源在不同添加水平下的能量贡献。在低能基础日粮中添加５％、１０％和１５％的葡萄糖或将豆油、黄油和牛脂三种脂肪,１～３周以１％和２％、４～６周以１．５％和３％两个水平添加到基础日粮中。通过脂肪添加组与葡萄糖组生长性能对照,根据生长性能相等的原则得出每一脂肪添加水平相应的葡萄糖水平,根据葡萄糖代谢能值（３．６４ｋｃａｌ／ｇ干物质）求出脂肪的能值。试验结果表明：黄油和牛脂在低水平（１％～１．５％）添加时其有效能值超出总能值（９．４ｋｃａｌ／ｇ）,其有效能值随着添加水平的提高而下降,而且饱和度越高下降愈明显;但对豆油而言,当添加水平在较小范围内（１％～３％）变化时其能值未见下降。     

Effect of food enzymes on AME and composition of digesta from broiler chickens fed on diets containing non-starch polysaccharides isolated from lupin kernel

1. The effects of lupin non-starch polysaccharides (NSPs) on apparent metabolisable energy (AME) and composition of digesta from broiler chickens were examined in a dose-response experiment in conjunction with a single combination of 2 commercial enzyme products known from previous studies to partially depolymerise NSPs in diets containing sorghum, casein and lupin kernel. The 7-d experiment was conducted on broiler chickens (24 to 31 d of age) in metabolism cages. 2. The basal diet used in this study contained (in g/kg) sorghum (low tannin) 800, casein 134, celite 20 and vitamins and minerals 46. The inclusion rate for each enzyme product was 0.2 g/kg. Lupin kernel isolate (containing 560 g/kg total NSPs) replaced some of the sorghum and casein. The dose rates of lupin kernel isolate (50, 100 and 150 g/kg) were equivalent to dietary inclusion rates of 80, 160 and 240 g/kg, approximately, of untreated lupin kernel from Lupinus angustifolius cultivar Gungurru. 3. Inclusion of lupin kernel isolate in the diet depressed AME and bird performance, and raised ileal viscosity and excreta moisture, in a dose-dependent manner. 4. A combination of 2 proprietary enzyme products improved dietary AME by 0.3 MJ/kg dry matter. Enzymes reduced excreta moisture when inclusion of lupin kernel isolate was 50 g/kg (equivalent to lupin kernel at 80 g/kg, approximately) but not at higher inclusions. 5. Food enzymes partially depolymerised some insoluble NSPs in lupin kernel isolate, which increased ileal viscosity and soluble NSP content of digesta. 6. It was concluded that development of appropriate exogenous enzyme products could lead to lupin NSPs being used as an energy source for poultry.     

Interactions between fats of differing chemical content: apparent metabolisable energy values and apparent fat availability

1. Tallow (A) and rape oil (E) were obtained for evaluation. They were blended in the ratios A95:E5, A90:E10 and A80:E20. The three blends together with the two pure fats were each included at 40, 80 and 120 g/kg into a basal diet. 2. The experimental diets were evaluated for apparent metabolisable energy corrected to zero nitrogen retention (AMEN MJ/kg) and apparent fat availability (g/kg) using 6 replicates of a cage of two male broiler chicks 14 d old and 8 replicates of a cage of one Rhode Island cross cockerel approximately 1 year old. Diets were fed for 72 h then removed for 24 h. This was followed by a 48 h period when food was available ad libitum and a further 24 h of starvation. A total collection of excreta was undertaken each 24 h for the latter 72 h period. 3. Evaluation of AMEN and apparent fat availability for the individual fat blends was achieved through both linear and quadratic regression. 4. Synergism, as demonstrated by a higher determined than calculated AMEN value, was detected with fat blends fed to chicks but not cockerels and only at rates of inclusion beyond 80 g/kg. 5. No consistent differences between AMEN determined through calorimetry or AME determined with reference to apparent fat availability multiplied by fat gross energy were detected.     

Importance of amino-acid and electrolyte balance in experimental diets used to determine the apparent metabolisable energy (AME) value of wheat

1. An experiment was done with male, Ross broiler chicks to study the effect of diet composition and electrolyte balance on the measurement of diet AME and performance parameters in diets containing high levels of wheat inclusion. 2. The control diet (G) was based on wheat (667 g/kg) with full-fat soya, soyabean meal, Extrupro and herring meal providing the protein supplements. The experimental treatments were based on 2 diets, one based on wheat (790 g/kg) with casein as the protein supplement and the other containing 667 g/kg wheat plus casein, cellulose and starch. Each of these was formulated to contain one of three concentrations of sodium and potassium bicarbonate giving final values for dietary electrolyte balance of approximately 90, 180 and 280 meq/kg diet. 3. DM intake was numerically lower with the lower level of wheat inclusion and LWG (P < 0.05) and gain:food (P < 0.001) were reduced. ME:GE was similar for the two levels of wheat/casein but higher (P < 0.001) than for the control diet. 4. The two higher electrolyte balances improved DM intake (P < 0.01), LWG and gain:food (P < 0.01) compared with the diets containing no added bicarbonate. ME:GE was unaffected by electrolyte inclusion. 5. Viscosity of ileal digesta supernatant fell (P < 0.01) with increasing bicarbonate inclusion but the value for the highest electrolyte level was still higher than for the control diet. 6. It is concluded that addition of both arginine and electrolyte is needed with a wheat/casein diet to improve performance to levels seen with a more commercial diet but that the determination of diet AME, with the type of fat addition used in this study, is unaffected by electrolyte balance. The interaction between electrolyte balance and in vivo viscosity requires further study.     

Effect of wheat content, fat source and enzyme supplementation on diet metabolisability and broiler performance.

1. A 3x3x2 factorial experiment studied the interactions of fat source (tallow, soya, tallow:soya [2:1] blend), wheat level (700, 350, 0 g/kg) and enzyme inclusion (Avizyme 1300, absent, present) in diets for broilers fed ad libitum in individual cages from 7 to 35d. Bird performance, fat digestibility, viscosity of ileal contents and diet metabolisability (AME) were measured. 2. There were no significant effects of fat source on bird performance. However, there was a significant effect on fat digestibility, which was highest for soya and lowest for tallow. Diet AME content was also significantly affected by fat source and reflected differences in fat digestibility. 3. Dry matter (DM) intake, liveweight gain (LWG) and gain:food were all reduced at 700 g wheat/kg. Viscosity of ileal contents increased with increasing wheat inclusion. 4. There were no significant effects of enzyme on DM intake or LWG but gain:food was improved by 2%. Diet AME content was increased with enzyme addition, the effect being greatest (9%) with tallow at 700 g wheat/kg. 5. Viscosity of ileal contents was reduced and fat digestibility increased with enzyme addition and there were significant wheat enzyme interactions attributable to no differences with zero wheat but marked responses to enzyme at 700 g wheat/kg. 6. The results confirm important interactions between wheat content and fat composition in relation to fat digestibility, AME content and food efficiency.     

生物秸秆对肉鸡表观代谢能的影响及替代玉米适宜比例的研究

本试验旨在研究肉鸡对生物秸秆的表观代谢能及其替代玉米的适宜比例.生物秸秆代谢能的测定试验选择24只42日龄健康的爱拔益加(AA)肉鸡,随机分为3个处理,每个处理8只鸡.处理1饲喂含8％生物秸秆的基础饲粮,处理2饲喂以30％的生物秸秆代替基础饲粮中能量饲料和蛋白质饲料的饲粮,处理3采用强饲法进行测定.生物秸秆代替玉米的试验选择150只42日龄健康的AA肉鸡,随机分为5个处理,每个处理5个重复,每个重复6只鸡.对照组饲喂基础饲粮,试验组分别在基础饲粮中用4％、8％、12％生物秸秆代替玉米(代谢能按照差量法计算结果12.46 MJ/kg计)及8％生物秸秆代替玉米(代谢能按照强饲法计算结果5.30 MJ/kg计,添加豆油,使其代谢能水平与对照组相同).结果表明:1)基础饲粮的代谢能为12.63 MJ/kg,采用差量法推算出肉鸡对生物秸秆的表观代谢能为12.46 MJ/kg,而采用套算法和强饲法测定生物秸秆的表观代谢能分别为4.38和5.30 MJ/kg.2)与对照组相比,4％和8％的生物秸秆代替玉米组中性洗涤纤维和酸性洗涤纤维的代谢率显著升高(P＜0.05),而12％的生物秸秆代替玉米组表观能量的代谢率显著降低(P＜0.05).由此得出,套算法和强饲法低估了生物秸秆的表观代谢能,而差量法更能准确反映生物秸秆的表观代谢能;在肉鸡饲粮中生物秸秆可以替代4％ ～8％的玉米.     

不同处理玉米秸秆营养成分及其肉鸡表观代谢能评定

本试验旨在评价不同处理玉米秸秆营养成分及其肉鸡表观代谢能。选择40只42日龄健康AA商品肉鸡,随机分为8个处理,每个处理5只鸡。直接法分为3个处理组,分别为强饲15 g 100%未处理秸秆、50 g 100%糖化秸秆、50 g 100%酵母发酵秸秆;差量法分为5个处理组,即基础饲粮组和试验组。试验组分别在基础饲粮中添加4%、8%、12%糖化玉米秸秆和8%酵母发酵秸秆替代等量玉米。通过饲养试验验证差量法和直接法对糖化玉米秸秆代谢能测定的准确性。结果表明:与未处理玉米秸秆相比,糖化秸秆中还原糖和钙含量分别增加8.08倍和9.31倍(P<0.05);与糖化玉米秸秆相比,酵母发酵秸秆中还原糖降低78.69%(P<0.05),真蛋白提高29.64%(P<0.05),总氨基酸提高41.01%(P<0.05);通过直接法得出糖化玉米秸秆和酵母发酵玉米秸秆的表观代谢能分别为4.85、4.75 MJ/kg;差量法测定糖化玉米秸秆在饲粮中添加4%、8%和12%时表观代谢能分别为15.85、15.81、14.38 MJ/kg,高于酵母菌发酵玉米秸秆(P<0.05);通过饲养试验验证,差量法测定的表观代谢能结果可信。结果显示,糖化玉米秸秆代谢能高于酵母发酵秸秆和玉米,可以作为肉鸡的饲料能量原料。     

Strategies to improve the nutritive value of rice bran in poultry diets. II. Changes in oil digestibility,metabolisable energy and attempts to increase the digestibility of the oil fraction in the diets of chickens and ducklings

1. In experiment 1, the effects of age on oil digestibility and apparent metabolisable energy (AME) were measured in chickens and ducklings between 3 and 28 d of age on a diet with 400 g rice bran/kg. In experiment 2, a biosurfactant and a food lipase were added to diets of chickens containing 200 and 400 g rice bran/kg. In experiment 3, chicken diets containing 0 or 400 g rice bran/kg were supplemented with a food lipase (2 concentrations) or a food enzyme or their combination. 2. In experiment 1, oil metabolisability and AME increased substantially as chickens aged. Oil metabolisability was much higher in ducklings, when comparisons were made with chickens of similar age. 3. In experiment 2, lipase or biosurfactant gave no improvement in bird performance. Growth rate and food conversion ratio were, respectively, 23% and 10% better on diets with 200 compared to 400 g rice bran/kg. 4. In experiment 3, there was a significant growth response to lipase plus the enzyme mixture on the diet with 200 g rice bran/kg. On the diet with 400 g rice bran/kg, growth improvement was seen with the enzyme mixture only. 5. In experiment 3, enzyme addition did not increase oil metabolisability or AME. At 4 to 8 d of age AME was higher on the diet without rice bran but oil metabolisability was the same as on the diet with rice bran. At 19 to 23 d of age AME was similar but oil metabolisability was higher on the diet with rice bran than without. Droppings' dry matter was higher on diets without than with rice bran (32.4 vs 27.1%). 6. The response to lipase and the combination of this and a food enzyme suggest that there may be benefit in examining this interaction further although they had no effect on oil metabolisability or on AME. It is concluded that a stable AME for rice bran cannot be provided for chickens until at least 21 d of age.     

European reference method of in vivo determination of metabolisable energy in poultry: reproducibility, effect of age, comparison with predicted values

1. Apparent metabolisable energy corrected to zero-nitrogen retention (AMEn) was measured using the European reference procedure in 9 European laboratories. Seven pelleted diets were evaluated. AMEn was measured with adult cockerels and young birds. 2. Between-laboratory standard deviations were for dry matter (DM) 12.5 g/kg, gross energy 0.085 MJ/kg DM, Kjeldahl nitrogen 0.768 g/kg DM, AMEn (adults) 0.256 MJ/kg DM, and AMEn (young) 0.337 MJ/kg DM. Corresponding coefficients of variation between laboratories were 1.42, 0.45, 2.15, 1.88 and 2.60% respectively. 3. AMEn values of experimental diets were always significantly lower when measured with young birds. This effect was more pronounced when diets contained added fat. 4. Tallow or soyabean oil were incorporated into two basal diets at 40 g/kg inclusion rate. No significant differences were observed between AMEn values of either diet with adults or young birds, suggesting that AMEn energy values of these fats are indistinguishable at this inclusion rate. 5. Similar AMEn values were obtained in young birds by estimating nitrogen accretion, either by the difference between intake and excreta nitrogen or by measuring body weight gain. Determined AMEn values were very similar to those predicted using three different regression equations.     

Growth Performance,Meat Yield,and Economic Responses of Broilers Fed Diets Varying in Metabolizable Energy from Thirty to Fifty-Nine Days of Age

Two studies examined responses of broilers to diets varying in AME from 30 to 59 d of age. A 59-d termination allows for evaluation of energy needs applicable to “big bird” programs, because research on nutritional needs for such programs is warranted. Two experiments were conducted: experiment (exp.) 1 having low temperatures whereas exp. 2 used moderate temperatures. The treatments in exp. 1 and 2 were AME concentrations ranging from 3,175 to 3,310 kcal/kg with CP, TSAA, and Lys being identical across all treatments. In exp. 2, an additional treatment consisted of a diet containing 3,310 kcal of AME/kg with CP, TSAA, and Lys being increased by 4% of those specifications used in the other treatments so as to minimize differences in energy:CP ratio.In both experiments, feed consumption and conversion decreased linearly as dietary AME increased, but breast meat yield was reduced with the high AME diet and only increasing amino acids in exp. 2 ameliorated the negative effect. Live production costs and gross feeding margin (bird return over feed costs) were optimized in exp. 1 with 3,220 kcal of AME/kg of diet, but 3,310 kcal of AME/kg of diet and increased amino acids were needed in exp. 2 for improved monetary returns. In both experiments, broilers had similar caloric consumption indicating that these broilers can compensate to varying dietary AME concentrations within practical limits. These results demonstrated that the response to dietary AME was more pronounced under moderate ambient temperatures.     

Effect of dietary levels of vitamin E (all-rac-tocopheryl acetate) with or without added fat on weanling pig performance and tissue alpha-tocopherol concentration

Two experiments involving 496 cross-bred pigs evaluated the efficacy of various dietary levels of vitamin E, with or without supplemental fat, on postweaning pig performance and weekly serum and terminal tissue alpha-tocopherol concentrations. The first trial involved 248 pigs weaned at an average of 15 d of age and 4.8 kg BW. The experiment was a randomized complete block design conducted in seven replicates. Vitamin E was added as dl-alpha-tocopheryl acetate at 0, 20, 40, 60, 80, 100, 150, or 200 IU/kg diet. Pigs were bled initially and at 7-d intervals for a 42-d period. Liver and s.c. adipose tissue samples were collected from six pigs per treatment group at 42 d. In Exp. 2, a 2 x 4 factorial arrangement of treatments in a randomized complete block design was conducted in seven replicates. The experiment used a total of 248 pigs weaned at 19 d of age and averaged 6.4 kg BW. Four vitamin E levels (0, 20, 40, and 60 IU/kg diet) and two added fat levels of 0 or 5% were fed for 35 d. Four pigs per treatment pen were bled weekly, and at 35 d a total of four pigs per treatment group were killed and liver, heart, and s.c. adipose tissues were collected and analyzed for alpha-tocopherol. The basal diet in both experiments contained an average 7.9 IU for period 1, and later diets averaged 11.0 IU vitamin E/kg. In both experiments serum alpha-tocopherol concentrations declined from weaning to 7 d after weaning and continued to decline each week after weaning when the basal diets were fed. Serum alpha-tocopherol concentrations increased (P < 0.01) each week as the dietary vitamin E level increased in both experiments. In Exp. 2, when fat was added to the diet serum alpha-tocopherol concentrations were higher (P < 0.01) than in diets without added fat. Liver, heart muscle, and adipose tissue alpha-tocopherol concentrations increased (P < 0.01) as vitamin E level increased, but at the higher dietary vitamin E level the liver surpassed the adipose tissue in its alpha-tocopherol concentration. Liver and adipose alpha-tocopherol concentrations were higher (P < 0.01) when fat was added to the diet. These results indicate that supplementation of 40 to 60 IU/kg diet with added fat resulted in a relatively constant balance of serum and tissue concentration of alpha-tocopherol during the nursery period, but when fat was not supplemented a dietary vitamin E level of 80 to 100 IU/kg diet may be needed. The current NRC recommendations for vitamin E for the pig from 5 to 20 kg BW may need to be reevaluated.     

Fat digestibility in Equus caballus follows increasing first-order kinetics

The digestibility of ether extract varies greatly from forages to grains and further to added fats consisting mainly of triglycerides. This variation has been attributed to two main factors, the presence of nonhydrolyzable substances in the ether extract, especially in leafy foods, and the dilution of endogenous fecal fat. A compilation of results from 188 equine digestion balance observations on five basal feeds and 18 test feeds with added fats demonstrated a true digestibility of fat approaching 100% and an endogenous fecal fat of 0.22 g x d(-1) x kg BW(-1). The results revealed that nonhydrolyzable ether extract and endogenous fecal fat were insufficient to account for the difference between true digestibility and apparent digestibilities of ether extract in basal feeds and partial digestibilities of added fats in test feeds. A third possible contributing factor was demonstrated: an increasing first-order relationship between observed digestibilities (D, %) and the fat content of the feed (F, g/kg): D = 92.0 - 92.0e(-F/342). r2 = 0.81, P < 0.001. This equation indicates that 46% digestibility (half maximum) occurs at an ether extract or fat content of 24 g/kg, which is common in forages. It is consistent with fat digestibility or efficiency of absorption being a function of the rate of lipolysis, especially when residence time in the small intestine is limited. Consequently, we suggest that the kinetics of lipases, which are difficult to measure, may contribute to low digestibility when substrate concentration in the small intestine is low due to a low fat content in food. The status of vitamins A and E might be affected by low dietary fat contents and might be improved by fat supplementation.     

Potential of chemical regulation of food intake and body weight of broiler breeder chicks

1. Two experiments were performed to evaluate the potential of phenylpropanolamine hydrochloride and monensin sodium as appetite- and weight-control agents for Indian River broiler breeder chicks. 2. In experiment 1, a total of 300 day-old sexed broiler breeder chicks were individually weighed and placed in battery cages. They were randomly assigned to 5 dietary treatments, namely 0, 50, 100, 200 and 400 mg/kg of phenylpropanolamine hydrochloride added to a maize-soyabean meal basal diet. 3. In experiment 2, a total of 400 day-old sexed broiler breeder chicks were randomly assigned to 10 dietary treatments which were a combination of two concentrations of dietary crude protein (200 and 150 g/kg) and 5 different concentrations of added drugs in the diet, namely 0, 500 and 800 mg/kg of phenylpropanolamine hydrochloride and 200 and 300 mg/kg of monensin sodium. 4. Food consumption and body weight gain were significantly reduced by feeding diets containing the drugs but mortality was not significantly affected. Birds showed evidence of increased tolerance, with age, to phenylpropanolamine but not to monensin. 5. Monensin sodium, at high inclusion rates, was found to be a more potent and effective appetite- and growth-depressing agent for broiler breeder chicks than phenylpropanolamine and may have application in broiler breeder production using an ad libitum feeding programme.     

Effects of increasing dietary concentrations of specific structured triacylglycerides on performance and nitrogen and energy metabolism in broiler chickens

Specific structured triacylglycerides (STG) containing medium chain fatty acids in sn-1,3 positions and a long chain fatty acid in sn-2 position were prepared from rapeseed oil and capric acid (C10:0). A total of 80 female broiler chickens (Ross 208) were randomly allocated into five dietary treatments as two series of 40 chicks: a basal diet with graded levels of STG of 0, 20, 40, 60 and 80 g/kg diet at the expense of rapeseed oil were fed to the chickens in groups of four. At 12 d of age the chickens were placed pair-wise in metabolism cages. The grower period (d 13-36) was divided into four consecutive balance periods each of 6 d. Two 24 h measurements of gas exchange in two open-air circuit respiration chambers were performed during the second and third day of each balance period. During the whole experiment there was a negative effect of the inclusion of STG on average feed intake. However, this only slightly affected average daily weight gain. Feed conversion efficiency improved linearly with the inclusion level of STG. Daily gain adjusted to mean daily feed intake increased linearly with inclusion rate of STG, indicating that the weight gain was affected by both feed intake and the enhancing effect on digestibility of STG. Weight of small intestine and colon decreased with increasing inclusion of STG. Utilisation of dietary protein relative to intake increased while that of retained fat tended to decrease resulting in a decreased utilisation of metabolisable energy (RE/ME) in birds receiving STG. Heat production (HE) was slightly lower in the STG groups. More of the dietary fat was oxidised when more STG was added, although the total amount of fat in the diets was kept constant.     

Metabolisable energy value and digestibility of fat and fatty acids in linseed determined with growing broiler chickens

1. In the first experiment, the AMEN of linseed was evaluated at rates of 40, 80, 160 and 240 g/kg in a basal diet with broiler chickens aged 28 d using the total collection method. 2. Increasing the concentration of linseed decreased the AMEN of diet, from 11.78 to 8.75 MJ/kg DM, and AMEN of linseed, from 16.64 to -2.96 MJ/kg DM. The negative values clearly indicated that linseed interacted with the other dietary ingredients and impaired their energy utilisation. 3. In the second experiment, a semipurified diet with graded addition of linseed (80, 120, 160 and 240 g/kg DM) was evaluated for crude fat and fatty acid apparent digestibilities. The coefficients decreased from 0.602 to 0.359 for crude fat and from 0.661 to 0.352 for individual fatty acids as the level of linseed increased. 4. In both experiments, a quadratic regression model explained the relationship between data better than the linear model. 5. The presence of mucilage and other antinutritional factors in linseed might explain the results obtained in this study.     

产蛋种鸡蛋氨酸需要量的研究

本试验研究了北京红鸡父母代产蛋种鸡２１～４５周龄真可利用蛋氨酸的需要量。试验日粮为玉米—豆粕型。３个基础日粮的粗蛋白水平分别为１４．５％、１６．５％和１８．５％,蛋氨酸水平分别为０．２１％、０．２４％和０．２９％。每个基础日粮添加４个蛋氨酸水平：０、０．０５％、０．１５％和０．３０％。其它氨基酸含量都满足ＮＲＣ推荐需要量,且随粗蛋白水平升高而按比例增加。日粮含表观代谢能均为１１．２９ＭＪ／ｋｇ。共设有１２个试验处理,每个处理有８个重复,每个重复有２２只父母代产蛋母鸡。北京红鸡父母代种鸡２１～４５周龄,平均产蛋率是７６％时,在１４．５％、１６．５％和１８．５％３个粗蛋白水平下,用产蛋率指标确定的每日每只鸡总蛋氨酸的需要量分别是３１７ｍｇ、３４８ｍｇ和４１４ｍｇ;真可利用蛋氨酸的需要量分别是２８０ｍｇ、３０８ｍｇ和３６６ｍｇ;总含硫氨基酸的需要量分别是６１０ｍｇ、６２６ｍｇ和７９１ｍｇ;真可利用含硫氨基酸需要量分别是５３７ｍｇ、５７３ｍｇ和６７２ｍｇ。试验鸡的生产性能没有由于提高日粮粗蛋白水平而得到显著改善。添加蛋氨酸可以显著改善种鸡的生产性能。饲喂添加比例合适的蛋氨酸和赖氨酸、含粗蛋白１４．５％的蛋鸡日粮,可     

Influence of dietary phosphorus concentration on the digestibility of phosphorus in monocalcium phosphate by growing pigs

An experiment was conducted to test the hypothesis that the dietary inclusion rate of P does not influence the digestibility of P. The experiment was conducted at 4 experiment stations where the same protocol was followed. A total of 60 growing pigs (initial BW: 22.22 +/- 2.13 kg) were allotted to 6 dietary treatments with 10 replications per treatment. All pigs were placed in metabolism cages that allowed for the total, but separate, collection of urine and fecal materials. Six diets were formulated. The basal diet was based on corn (54.2%), soybean meal (20%), and cornstarch. No inorganic P was used, and the total concentration of P in the basal diet was calculated to be 0.29%. Five additional diets were formulated by adding monocalcium phosphate (MCP) in increments of 0.34% to the basal diet and thereby creating diets that were calculated to contain 0.36, 0.43, 0.50, 0.57, and 0.64% total P, respectively. Ground limestone was also added to these diets to maintain a calculated Ca:P ratio of 1.2:1. The balances of Ca and P and the apparent total tract digestibility (ATTD) of Ca and P were calculated for each diet. The contribution of P from the basal diet was then subtracted from the MCP-containing diets to calculate the balance and ATTD for P in MCP. Results of the experiment showed that the absorption and retention of both Ca and P increased (linear, P < 0.001) with increasing concentrations of Ca and P in the diet. The ATTD for Ca ranged from 62.3 to 66.8% and was not influenced by the dietary concentration of Ca. However, the ATTD for P increased from 38.4 to 65.2% as increasing levels of MCP were added to the diet (linear, P < 0.001). Increasing P intake from MCP increased (linear, P < 0.001) the excretion of P in the feces, but the quantity of P that was absorbed and retained also increased (linear, P < 0.001) as more P from MCP was added to the diet. When measured as a percentage of P intake, P retention was not influenced by the dietary P concentration. The ATTD for P in MCP ranged from 79.5 to 88.5% and was not affected by the concentration of P in the diet. Results of this experiment demonstrated that the digestibility and absorption of P from MCP are not influenced by the dietary concentration of P.     

The effect of herbs and their associated essential oils on performance, dietary digestibility and gut microflora in chickens from 7 to 28 days of age

1. The effect of the dietary inclusion of 5 culinary herbs or their essential oils on the growth, digestibility and intestinal microflora status in female broiler chicks was assessed. From 7 to 28 d of age, either a basal control diet without supplement was given or one of 10 others, consisting of the basal diet with either 10 g/kg herb (thyme, oregano, marjoram, rosemary or yarrow) or 1 g/kg of essential oil. 2. Body mass (BM) and feed consumption (AFC) were measured on a weekly basis and used to calculate chick performance. Total viable counts of lactic acid bacteria, coliforms, anaerobes and Clostridium perfringens were determined at 25 d. Apparent nutrient digestibilities were calculated from the measured values for gross energy, nitrogen (N), dry matter (DM) and organic matter, and sialic acid concentration was also measured. 3. Generally, dietary thyme oil or yarrow herb inclusion had the most positive effects on chick performance, while oregano herb and yarrow oil were the poorest supplements. Only thyme and yarrow in these diets had a different effect when used as a herb or oil on weight gain and BM. 4. Dietary treatment had no effect on the intestinal microflora populations, apparent metabolisable energy (AME) or the calculated coefficients of digestibility. Sialic acid concentration was greatest in the birds given dietary thyme oil, compared with all other treatments except those birds receiving marjoram oil, rosemary herb and the controls. However, less sialic acid was excreted in those birds given diets with oregano or rosemary oils, or oregano herb, than in the controls. 5. Plant extracts in diets may therefore affect chick performance, gut health and endogenous secretions, although the chemical composition of the extract appears to be important in obtaining the optimal effects.