复合酶制剂对北京填鸭胴体性状、体脂沉积和营养物质表观消化率的影响

本试验旨在研究饲粮复合酶制剂水平对北京填鸭胴体性状、体脂沉积和营养物质表观消化率的影响。选取35日龄健康、大小均匀的雄性北京鸭96只,随机分成4个组,每个组6个重复,每个重复4只鸭。对照组饲喂玉米-豆粕型基础饲粮,试验1组、试验2组和试验3组饲粮分别在基础饲粮中添加100、200和300 mg/kg的复合酶制剂,试验鸭在35和36日龄饲粮填饲量分别为260和300 g,之后5 d各组饲粮填饲量均为400 g/d。试验期为7 d。结果表明:1)饲粮复合酶制剂水平对北京填鸭屠体重、屠体率、全净膛重、全净膛率、腿肌重、腿肌率、龙骨长和胸宽均无显著影响(P0.05),而对北京填鸭增重、胸肌重、胸肌率、胸肌厚、肌胃重和肌胃率有显著影响(P0.05)。试验2组和试验3组北京填鸭胸肌重和肌胃重分别比对照组显著提高了7.88%和7.60%(P0.05)。2)饲粮复合酶制剂水平对北京填鸭皮脂重、皮脂率、腹脂重、腹脂率、肝脏重、肝重率和肝脂率均无显著影响(P0.05)。试验1组皮脂厚与对照组相比显著提高了16.2%(P0.05)。3)饲粮复合酶制剂水平对北京填鸭干物质和总能表观消化率无显著影响(P0.05),而对北京填鸭粗蛋白质表观消化率有显著影响(P0.05)。由此可见,饲粮中添加复合酶制剂对北京填鸭体脂沉积无显著影响,但能够提高饲粮中粗蛋白质表观消化率,并促进胸肌和肌胃的生长发育。     

Effects of alfalfa meal on carcase quality and fat metabolism of Muscovy ducks

1. The effects of alfalfa meal on carcase quality and fat metabolism of Muscovy duck were evaluated. The objective of this research was to establish whether alfalfa meal can reduce fat content and improve carcase quality of Muscovy duck. Animal products with a high fat content present a risk factor for many diseases. Reducing fat content in poultry products is an important goal for the poultry industry.

2. A total of 240 14-d-old white Muscovy ducks were selected and randomly allocated to 1 of 4 dietary treatments containing 0, 3, 6, and 9% of alfalfa meal for 5 weeks. Growth performances were recorded and carcase characteristics and lipid parameters were analysed.

3. Results showed that 3, 6, and 9% alfalfa meal in diet had no significant effects on growth performance of Muscovy ducks from 14 to 49?d of age. Ducks given 3, 6, and 9% alfalfa meal had significantly higher dressing percentage and lower abdominal fat percentage compared with those given no alfalfa meal. Ducks given 9% alfalfa meal had higher breast meat percentage compared with those given no alfalfa meal. The concentrations of triglyceride, total cholesterol, low density lipoprotein (LDL), very low density lipoprotein (VLDL) and free fatty acid in serum of ducks fed on alfalfa meal decreased. Alfalfa meal in the diet decreased abdominal fat percentage and improved carcase traits of Muscovy duck.

4. The study showed that dietary alfalfa meal decreased abdominal fat percentage and improved carcase traits, without an adverse effect on performance.     

Impact of feeding 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine supplemented maize-soybean-rapeseed meal diets on growth performance and carcase quality of broilers

1. This experiment was conducted to compare the effectiveness of DL-2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and DL-methionine (DLM) on growth performance and carcase quality of broilers in a 2 x 3 x 2 factorial experimental design including two methionine (Met) sources, three equimolar levels of Met supplementation and two sexes. 2. No difference was observed between the two Met sources in growth performance and muscle deposition from 10 to 49 d. With increasing Met levels, average daily gain was increased in the starter, grower and overall phases, average daily feed intake was increased in the starter phase, and feed:gain ratio was decreased in the grower and overall phases. Met supplementation increased breast muscle content and decreased abdominal fat content. Broilers given HMTBA had breast and thigh muscle coloration that was characterised as superior to those fed DLM. 3. These results indicated that Met supplementation improved growth performance and carcase quality irrespective of the Met sources. Compared to DLM, HMTBA has the same molar bioefficacy for improving the growth performance and carcase quality; however, HMTBA-fed birds had superior meat colour to DLM-fed birds.     

Growth pattern and carcase development in male ducks selected for growth rate.

1. Growth patterns of the whole body, eviscerated carcases, breast muscle, leg and thigh muscles and abdominal fat pads were compared in 4 lines (Lines A, B, C, and D) of male ducks selected for market weight (n = 1305) using growth curve analysis, allometric growth analysis and repeated measure analysis. At 49 d of age, Line A was heaviest, followed by Line B, Line C and Line D. 2. Ducks were fed ad libitum under 24-h lighting and 12 or 24 ducks were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights at time points from hatching until 53 d of age. 3. The Weibull function was chosen for growth curve analysis. The asymptote and inflection point from the Weibull growth curves identified 3 lines (Lines B, C, and D) with discrete body and carcase growth patterns but did not distinguish Line A from Line B. In all 4 lines the asymptote ranged from 4437 g to 3008 g for body weight and from 3334 g to 2098 g for carcase weight; the inflection point ranged from 22.5 d to 25.3 d for body weight and from 25.4 d to 29.6 d for carcase weight. 4. The allometric growth coefficient, relative to whole-body growth, was higher than 1.00 for breast muscle and lower than 1.00 for leg and thigh muscles during from 4 d to 53 d of age. 5. Body fat accumulation was estimated by abdominal fat. Line D accumulated more abdominal fat than other lines. The pattern of fat accumulation in Line D was different from Lines A, B and C and there were no differences between Lines A, B and C.     

不同填饲量对北京鸭胴体品质、体脂沉积和营养物质表观消化率的影响

旨在研究不同填饲量对北京鸭胴体品质、体脂沉积及营养物质表观消化率的影响。选取35日龄健康、大小均匀的W系雄性北京鸭96只,随机分成8个处理,每处理6个重复,每个重复2只鸭。基础日粮中加入0.5%的Cr2O3作为外源指示剂测定填鸭营养物质表观消化率,对照组自由采食,试验组在35和36日龄时分别填饲260和300g.d-1的基础日粮,之后5d各处理填饲量保持不变,分别为300、330、360、390、420、450、480g.d-1,试验期为7d。结果表明:(1)不同填饲量对北京鸭屠体率、全净膛率、胸肌率、腿肌质量和腿肌率影响不大(P>0.05),而对北京鸭胸肌质量影响显著(P<0.05),并随填饲量的增加呈现先升高后平稳的趋势,以胸肌质量为评定指标,采用直线折线模型进行估算的最适填饲量为390.7g.d-1。不同填饲量对北京鸭皮脂质量、皮脂率、腹脂质量、腹脂率、肝脏质量、肝重率和肝脂率均有显著的影响(P<0.05),但填饲量增加到一定值后,体脂沉积量保持稳定(P>0.05);(2)在填饲期,不同填饲量对北京鸭干物质和粗蛋白表观消化率影响显著(P<0.05),而对能量表观消化率影响不大(P>0.05)。以上结果表明,填饲能够快速增加北京鸭的体脂沉积,对胸肌生长发育影响显著,但随填饲量的增加,营养物质表观消化率下降,填鸭体脂沉积量不再增加。     

Abdominal fat weight and thickness as predictors of total body fat in broilers

In two experiments broilers of both sexes from two strains were reared to 16 weeks of age to determine how total body fat could be estimated and predicted from some carcase traits. In the first experiment, age, carcase weight and abdominal fat thickness were found to be significant factors in the prediction of total body fat weight estimated from abdominal fat weight. In the second experiment abdominal fat weight was the best predictor of total body fat weight, obtained by ether extraction of the minced whole carcase. Inclusion of abdominal fat weight in the prediction equation after carcase weight and abdominal fat thickness significantly improved the regression. If the carcase cannot be weighed and abdominal fat weight is not available, because of the more laborious nature of its determination, then the measurement of abdominal fat thickness can be useful in predicting the total body fat content.     

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0.5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.     

Lack of interrelationship between the effects of dietary factors and food withdrawal on carcase quality of broiler chickens

1. Four factorial experiments were carried out to determine whether there is any interrelationship between dietary energy-to-protein (E:P) ratio (experiments 1, 2 and 3) or pelleting the diet (experiment 4) and the duration of food withdrawal (FW), in their effect on carcase quality of broiler male chickens. The quality was evaluated by yields of carcase and breast meat, abdominal fat pad size, and the content and composition of the fat in the meat. The effect of sex on the response to FW was also determined in experiment 3 and that of age in experiment 4. 2. The diet with an E:P ratio higher than recommended decreased the weights of carcase and breast meat significantly (P 0.05) in 2 of the 3 experiments, and consistently increased the size of the abdominal fat pad and the fat content in thigh, but not in breast meat. Abdominal fat pad and the fat in meat of birds fed on this diet contained a significantly higher amount of oleic acid and a lower amount of linoleic acid, than the fat of birds fed on the diets with the recommended and the low E:P ratios. The pellets increased significantly the weights of carcase and breast meat and the relative size of abdominal fat pad. 3. FW for 24 h decreased significantly the weight at slaughter in all 4 experiments, carcase weight in 3 experiments, and breast weight in 1 experiment. However, it did not affect the relative size of the abdominal fat pad, the fat content in thigh and breast meat, and the composition of fatty acids in these tissues and in abdominal fat. None of the variables mentioned was affected significantly by the interaction between the dietary factors evaluated, sex or age of the birds on the one hand, and FW on the other hand. 4. It is concluded that the effect of 24 h of FW on weight at slaughter, carcase and breast meat weights and on fattening, is not affected by dietary E:P ratio, pelleting the diet, or sex and age of the broilers.     

Effect of dietary concentrations of fat and energy on fat deposition in broilers divergently selected for high or low abdominal adipose tissue

1. Fat deposition in abdominal, mesenterial, sartorial and gizzard adipose tissues (AT), liver, breast muscle, skin and carcase was studied in male broilers, selected for high (HF) and low (LF) abdominal fat and fed on diets differing in energy density and total fat content. 2. There were no significant differences in body weight in the experimental groups. The relative weight (g/kg body weight) of the dissected adipose tissues was higher in HF than in LF birds. Fat concentration in the AT (sartorial excepted), skin and body was higher in the HF compared with the LF birds. The lines did not differ significantly in liver and breast muscle fat content. 3. Abdominal AT was affected by selection or dietary fat more than other AT and total body fat. 4. In the HF birds increasing energy density from 12.3 to 13.4 MJ/kg (dietary fat kept constant: 5.46 g/MJ) significantly increased the weight of the abdominal, mesenterial and sartorial AT. Increasing dietary fat (at both energy densities) decreased the weight of the AT, whereas increasing both energy and fat did not affect it. In the LF birds, similar but milder and insignificant trends were observed. It is suggested that this interaction has biological significance.     

Evaluation of wet-feeding wheat-based diets containing Saccharomyces cerevisiae to broiler chickens

1. This experiment investigated the effects of water and Saccharomyces cerevisiae added to wheat-based diets on gastrointestinal, blood and performance parameters of broiler chickens. 2. A total of 160 one-d-old male broiler chicks were given air-dry or wet diets, with or without S. cerevisiae supplementation (0 and 20 g/kg air-dry feed) ad libitum to 42 d. 3. Feeding broilers with a diet mixed with water in a ratio of 1·2 : 1·0 increased body weight, feed intake, abdominal fat, carcase weight, feed transit time and blood HDL (high density lipoprotein) (without yeast). Supplementation with S. cerevisiae increased DM digestibility but reduced ileal pH, ileal coliform population and abdominal fat content. 4. There was a significant interaction between S. cerevisiae and wet feeding, with S. cerevisiae supplementation inducing a significant increase in body weight and feed intake but a reduction of relative abdominal fat and ileal pH of broilers fed on wet diets. 5. It is concluded that wet feeding improved growth performance by increasing feed intake and that the addition of a culture of S. cerevisiae had a growth stimulating effect, as the inclusion of yeast in wet wheat-based broiler diets generated greater responses than yeast in dry-based diets.     

Growth curve analyses in selected duck lines.

1. Growth patterns of male ducks from 4 lines (lines A, B, C and D) selected for market weight were analysed and compared to growth patterns of ducks in the respective line 7 generations earlier. Growth curves were analysed using procedures derived from the Weibull sigmoidal function and the linear-linear relative growth rate model and simple allometry. 2. The ducks were fed ad libitum under 24-h lighting throughout the experiment. At weekly intervals from the time of hatch through 70 d of age, 16 ducks from each line were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights. 3. Line A was the heaviest line, followed by line B, line C and line D. However, body weight, carcase weight and breast-muscle weight at 49 d of age were not significantly different between lines A and B. After 7 generations of selection, the breast-muscle yield was increased to >19% and the abdominal fat percent was reduced to <1.4% in all lines. 4. The Weibull growth curve analysis of body weight showed an increase in the asymptotes during selection, while the age of the inflection point remained constant in all lines (21.3 to 26.0 d). For breast-muscle growth, ducks reached the inflection point 12.8 to 14.3 d later than for body weight. Between line A and line B, asymptotes for body weight, asymptotes for breast-muscle weight and allometric growth coefficients of breast muscle and leg and thigh muscles from 14 to 49 d were not significantly different. 5. The relative growth rate model discriminated body and breast-muscle growth patterns of line A and line B. The initial decline in the relative body growth rate was less and the time to reach the transition was longer in line A than line B. On the other hand, the initial decline in the relative breast-muscle growth rate was greater in line A than line B.     

Corticosterone administration and dietary glucose supplementation enhance fat accumulation in broiler chickens

1. The effects of exogenous corticosterone administration and glucose supplementation on energy intake, lipid metabolism and fat deposition of broiler chickens were investigated. 2. A total of 144 three-d-old male chickens were randomly assigned to one of the following 4 treatments for 7 d: a low energy diet (10.9 MJ ME/kg, 200 g/kg CP) with or without corticosterone (30 mg/kg diet) and drinking water supplemented with glucose (80 g/l) or saccharine (2 g/l, control). 3. Body weight (BW) gain and breast and thigh muscle yields (% body mass) were all significantly decreased by corticosterone treatment. The relative cumulative feed intake (RCFI) and relative ME intake (RMEI), rather than the feed (FI) or ME intake (MEI) were increased by corticosterone administration. Both feed efficiency (FE) and caloric efficiency (CE) were decreased by corticosterone administration. Corticosterone administration had no obvious effect on water consumption. 4. Glucose supplementation had no influence on BW gain and breast and thigh muscle yield (as % of body mass). FI or RCFI was decreased while MEI or RMEI was increased by glucose supplementation. FE was improved by glucose treatment, whereas CE was reduced. 5. Liver weight and abdominal, cervical and thigh fat deposits were all significantly increased by either corticosterone or glucose treatment. 6. Plasma concentrations of glucose, urate, triglyceride, non-esterified fatty acids (NEFA), very low density lipoprotein and insulin were all significantly increased by corticosterone treatment. Glucose supplementation had no obvious influence on any of the measured plasma parameters except for NEFA, which were significantly increased. 7. Lipoprotein lipase activities in either cervical or abdominal adipose tissues, rather than in thigh fat tissue, were significantly elevated by either glucose or corticosterone treatment.     

Influence of dietary energy on bird performance,carcase parts yields and nutrient composition of breast meat of heterozygous naked neck broilers reared at natural optimum and summer temperatures

1. Heterozygous naked neck birds were raised under natural spring (average 21.2°C) and summer temperatures (average 27.1°C) to investigate the influence of dietary energy on broiler performance, carcase yield and nutrient composition of breast meat. 2. Birds were fed on a low energy diet of 12.12 MJ ME/kg, a medium energy diet of 12.96 MJ ME/kg and a high energy diet of 13.79 MJ ME/kg with 2 protein concentrations per energy treatment, 230 and 200 g/kg, from 0 to 3 and 3 to 7 weeks of age, respectively. 3. Summer rearing resulted in a decrease in body weight, body weight gain, carcase weight and carcase part yields of birds. 4. Increasing dietary energy from 12.12 to 13.79 MJ ME/kg increased body weight at 3 and 7 weeks, body weight gains from 0 to 3 and 3 to 7 weeks, carcase weights and relative abdominal fat weights of birds in a linear manner. There was no effect of dietary energy on the nutrient composition of breast meat. 5. It was concluded that there was no differences in dietary energy requirements of heterozygous naked neck birds when grown under natural optimum (21.2°C) and summer temperatures (27.1°C).     

2种共轭亚油酸异构体对小鼠肌内脂肪沉积和肌肉线粒体代谢的影响

试验旨在研究不同共轭亚油酸异构体对小鼠肌内脂肪沉积和肌肉线粒体代谢的影响.将成长到5周龄的雄性小鼠按体重分成3组(每组8只),适应1周后分别饲喂不添加、添加2％的顺9反11共轭亚油酸(c9,t11-CLA)和添加2％的反10顺12共轭亚油酸(t10,c12-CLA)的日粮,正试期1个月,监测其体重和体组成的变化,饲养试...     

Effect of dietary methionine on performance, carcase characteristics and breast meat composition of heterozygous naked neck (Na/na+) birds under spring and summer conditions

1. Heterozygous naked neck (Na/na+) birds and their normally feathered counterparts (na+/na+) were fed from 0 to 7 weeks on 3 diets differing in methionine concentrations. From 0 to 3 and 3 to 7 weeks, respectively, the concentrations were: low containing 4.3 and 3.3 g/kg; optimum containing 5.0 and 3.8 g/kg and; high with 5.7 and 4.4 g/kg under spring (optimum ambient temperature) and summer conditions (high ambient temperature). Performance, carcase characteristics and breast meat chemical composition were determined. 2. Summer rearing resulted in a decrease in body weight, body weight gain, food consumption, and yields of carcase and breast. The summer temperature effect was more pronounced in males. Under summer temperatures, the protein content of the breast decreased while the fat content increased compared to birds reared in spring. 3. By 7 weeks of age, both genotypes reached similar body weights in the spring experiment while, in summer Na/na+ birds were 3.3% heavier and gained more in the period from 3 to 7 weeks than na+/na+ birds. Carcase and breast yields of Na/na+ birds were greater than in na+/na+ birds. 3. Second order polynomial coefficients of the dietary methionine effect were found to be significant for body weight at 3 and 7 weeks. Daily body weight gain between 3 and 7 weeks was linearly affected by the dietary methionine concentration. There was no interaction between genotype and methionine. 4. Methionine had no significant effect on carcase yield. Second order polynomial coefficients of the dietary methionine effect were found to be significant for breast yield while the methionine effect on abdominal fat was linear. Na/na+ females fed on the low methionine diet had lower protein content than the Na/na+ males. 5. It is concluded that the methionine requirement of Na/na+ birds did not differ from that of their normally feathered counterparts under either spring or summer ambient temperature conditions.     

Effects of sex and inclusion of dried distillers grains with solubles on slaughter yield and meat characteristics of Pekin ducks

1. The effects of dried distillers grains with solubles (DDGS) dietary inclusion concentration, and sex, on body weight, slaughter efficiency and meat characteristics of Pekin ducks (Anas platyrhynchos f. domestica, strain P55) were studied.

2. Sexed ducklings (n?=?160) were divided randomly into 4 groups (each with 4 replicates). From d 1 to d 21, all the birds received the same commercial feed, then from 22 to 49 d of age the ducks were fed in the following groups: control (commercial feed) and three experimental groups (15%, 25% and 30% inclusion of DDGS). All ducks were weighed individually at d 1, 21 and 49. On the day of slaughter, 5 males and 5 females, of body weight close to the average weight for group and sex, were selected from each group, slaughtered and the following parameters were evaluated: slaughter yield, weight, and percentage of particular elements of carcase, physical and chemical characteristics of meat.

3. The results obtained showed that DDGS included from 22 to 49 d of rearing, at concentrations up to 30%, in a commercial Pekin duck diet did not affect the live body weight, slaughter yield, weight, and percentage of breast and leg muscle, skin with subcutaneous fat, and abdominal fat. There were no differences in physical characteristics (pH₁₅, pH_24, meat colour values L*, a*and b*, and hygroscopicity) of breast muscle, as well as in cholesterol content. DDGS addition at 30% significantly increased fat content in male, and crude protein in female, breast meat. Sex effect was observed only in a few traits and was diet dependent. Final body weight of females fed 30% DDGS was significantly lower than males; in the control and 15% DDGS group females had higher percentage of skin with subcutaneous fat.

4. The results obtained, and relative costs of feeds produced, allows the recommendation of DDGS addition at up to 30% to commercial Pekin duck diets from 22 d of age.     

溶血卵磷脂对肉仔鸡脂类代谢的影响

选200羽1日龄AA肉仔鸡,随机分成对照组和试验组(每组10个重复),试验组日粮添加0.1%溶血卵磷脂,研究溶血卵磷脂对肉鸡脂类代谢的影响。结果表明:溶血卵磷脂降低肝脏系数和肝脂率(P>0.05)、血清总甘油三酯与低密度脂蛋白胆固醇(LDL-C)(P>0.05)、LDL-C/HDL-C和葡萄糖含量(P<0.05),提高高密度脂蛋白胆固醇(HDL-C)和游离脂肪酸含量(P<0.05),上调肉仔鸡肝脏载脂蛋白B(P<0.01)和脂肪酸合成酶(P=0.155)mRNA表达水平;而对肉仔鸡的42日龄体重、腹脂率、皮下脂肪厚、肌间脂肪厚、腿肌和胸肌含脂率以及血清总胆固醇、三碘甲腺原氨酸、四碘甲腺原氨酸、促甲状腺激素刺激激素和胰岛素含量均无显著影响(P>0.05)。结果提示:溶血卵磷脂对肉仔鸡有减少肝脂肪沉积及降血脂作用。     

日粮共轭亚油酸对不同性别肉仔鸡生长性能及脂肪代谢相关酶的影响

试验采用2×2因子设计(日粮类型0%或1%CLA,肉鸡性别)研究日粮CLA对不同性别肉仔鸡生长性能、屠体性状和脂肪代谢相关酶的影响。结果表明:日粮中添加1%CLA可以显著增加各性别肉仔鸡各阶段的体增重,并改善了4～6、0～6周的饲料转化效率(P<0.05),可以显著提高各性别肉仔鸡的胸肌率、同时显著降低各性别肉仔鸡的腹脂率(P<0.05),显著降低了各性别肉仔鸡腹脂脂蛋白脂酶(LPL)活性及其mRNA相对表达量(P<0.05),显著降低了各性别肉仔鸡腹脂及肝脏硬脂酰辅酶A去饱和酶(SCD)mRNA相对表达量(P<0.05)。另外除体增重部分指标外,性别和日粮CLA对肉仔鸡屠体性状和脂肪代谢相关酶的影响不存在互作关系。     

Effect of conjugated linoleic acid on growth performances, carcase composition, plasma lipoprotein lipase activity and meat traits of chickens

1. The effects of dietary conjugated linoleic acid isomers (CLAs) on productive traits, carcase yield and meat quality were investigated in Beijingyou (Chinese) chickens. A total of 360 male chicks were allocated to 5 dietary treatments (0.00, 0.25, 0.50, 1.00 and 2.00% CLA) and fed for 126 d. 2. The results showed that CLA supplementation did not significantly influence body weight, but increased feed conversion and decreased intramuscular fat in breast and thigh muscles. Mortality was significantly higher in the control group. 3. The addition of 1.0 and 2.0% CLA decreased abdominal fat percentages. At CLA dietary levels greater than 0.5%, lipoprotein lipase activity in plasma was significantly decreased. 4. Hunter L* and a* values were not significantly affected by CLA supplementation. However, Hunter b* values were lower in chickens supplemented at levels greater than 0.5% CLA. Supplementing diets with CLA modified the fatty acid composition of breast muscle. The proportions of CLA, saturated and polyunsaturated fatty acids were increased whereas the proportion of monounsaturated fatty acids was decreased.     

饲粮精氨酸对0～21日龄樱桃谷肉鸭生长和免疫器官指数的影响

试验研究了饲粮中不同水平精氨酸(Arginin,Arg)对肉鸭生长、免疫器官重量和结构的影响。选用96只0日龄(刚出壳)樱桃谷鸭,随机分为4个处理,每个处理4个重复,每个重复6只鸭。分别饲喂Arg缺乏的基础饲粮(Arg含量为0.62%)和在基础饲粮中添加0.25%、0.50%、1.00%Arg的试验饲粮。试验期内测定肉鸭的生产性能。21日龄时,屠宰取胸腺、脾脏和法氏囊,测定免疫器官重量,计算免疫器官指数,并制作切片观察组织结构。结果表明,饲粮缺乏Arg显著降低肉鸭的增重(P0.01)和胸腺、脾脏和法氏囊的重量(P0.05);显著降低胸腺、脾脏指数(P0.05),而对法氏囊指数无显著影响(P0.05);添加Arg使鸭的胸腺小叶皮质增厚,胸腺小体增多,脾动脉周围淋巴鞘增厚,脾小结体积变大,法氏囊皱襞发达。说明饲粮Arg水平显著影响肉鸭生长和免疫器官的发育,饲粮Arg含量为1.12%时最佳。