Free availability of high‐energy foods led to energy over‐ingestion and protein under‐ingestion in choice‐fed broilers

The objective of this study was to compare energy and protein content of the diet selected by choice‐fed broilers with that of broilers fed a balanced diet. One hundred and eighty 1‐day‐old male broilers were randomly assigned in groups of 10 to one of three experimental treatments (n = 6). Control broilers were fed a standard balanced diet, whereas choice‐fed broilers were fed three foods which were more concentrated (Choice C+ treatment) or less concentrated (Choice C– treatment) in protein, carbohydrate or fat. We evaluated food intake behavior, nutrient intake, and performance parameters of broilers from 2 to 7 weeks of age. Choice C+ broilers showed enhanced preference for the high‐fat food, which led to higher energy intake and lower protein intake than those of control broilers at 2 to 4 weeks of age. Body weight, weight gain and feed conversion efficiency were negatively affected by diet selection of Choice C+ broilers. Choice C– broilers selected a balanced diet, and showed performance parameters similar to those of control broilers. Our results supported the hypothesis that free availability of high‐energy foods bias ingestive behavior of choice‐fed broilers toward selecting a diet with higher energy and lower protein than needed for normal growth.     

柑橘提取物对肉鸡运输应激后血浆生化指标、激素水平和抗氧化功能的影响

试验旨在研究柑橘提取物对肉鸡运输应激后血浆生化指标、激素水平和抗氧化功能的影响。选取360只28日龄快大型黄羽肉鸡,随机分2组（每组6个重复,每个重复30只鸡）,对照组饲喂不含抗生素的基础日粮,试验组饲喂添加10 mg/kg柑橘提取物的基础日粮。63日龄,从每个重复选6只鸡进行运输应激试验,分别运输0、2、4 h,运输结束后翅静脉采血取样。结果表明：①对葡萄糖（GLU）、胆固醇（CHOL）和尿素氮（BUN）而言,日粮处理和运输时间存在显著交互作用（P<0.05）。与对照组相比,试验组肉鸡血浆中BUN和CHOL含量显著低于对照组,运输2和4 h,试验组肉鸡血浆中GLU含量显著高于对照组（P<0.05）;运输应激显著影响对照组肉鸡血浆中BUN、CHOL和GLU含量（P<0.05）,随着运输时间的延长,BUN和CHOL含量逐渐提高,而GLU含量逐渐降低。②对于皮质酮（CORT）、三碘甲状腺原氨酸（T₃））和甲状腺素（T₄）而言,日粮处理和运输时间存在显著交互作用（P<0.05）。与对照组相比,运输2和4 h,试验组肉鸡血浆中CORT含量显著降低,而T₃和T₄含量显著提高（P<0.05）;运输应激显著影响对照组肉鸡血浆中CORT、T₃和T₄含量,运输后,肉鸡血浆中CORT含量显著提高,而T₃和T₄含量显著降低（P<0.05）。③对于谷胱甘肽过氧化物酶（GSH-Px）而言,日粮处理和运输时间存在显著交互作用（P<0.05）。与对照组相比,试验组肉鸡血浆中GSH-Px活性显著高于对照组（P<0.05）;运输应激显著影响对照组肉鸡血浆中GSH-Px活性,随着运输时间的延长,其活性显著降低（P<0.05）。综上,运输应激影响黄羽肉鸡机体的代谢水平、激素分泌和抗氧化功能,日粮中添加柑橘提取物可改善肉鸡的代谢水平,调控激素分泌和提高抗氧化能力,缓解运输应激对黄羽肉鸡的影响。     

Effects of Citrus Extract on Plasma Biochemical Indexes,Hormone Levels and Antioxidant Function of Broilers after Transport Stress

In order to study the effects of citrus extract on the plasma biochemical indexes,hormone level and antioxidant function of broilers after transport stress,a total of 360 twenty-eight-day-old fast-growing Yellow feather broilers were randomly divided into two groups (6 replicates per group,30 per replicate).The control group was fed basic diet without antibiotics,the experimental group was fed basic diet supplemented with 10 mg/kg citrus extract.At 63 days,six chickens were selected from each replicate for transport stress test for 0,2,and 4 h,respectively,and plasma sampling were conducted after transportation.The results showed that:① For glucose,cholesterol and urea nitrogen,there was a significant interaction between food treatment and transportation time (P<0.05).Compared with the control group,the contents of urea nitrogen and cholesterol in the plasma of broilers in the experimental group were significantly lower than that in the control group,and the content of glucose in the plasma of broilers in the experimental group was significantly higher than that in the control group (P<0.05).Transport stress significantly affected the content of urea nitrogen,cholesterol and glucose in the plasma of broilers in the control group,after transportation,the content of urea nitrogen and cholesterol increased significantly,while the content of glucose decreased significantly (P<0.05).② For corticosterone,triiodothyronine and thyroxine,there was significant interaction between food treatment and transport time (P<0.05).Compared with the control group,the content of corticosterone in the plasma of broilers in the experimental group was significantly lower than that in the control group,while the content of triiodothyronine and thyroxine in the experimental group was significantly higher than that in the control group (P<0.05).Transport stress significantly affected the content of corticosterone,triiodothyronine and thyroxine in the plasma of the control group,after transportation,the content of corticosterone in the plasma of the broiler significantly increased,while the content of triiodothyronine and thyroxine significantly decreased (P<0.05).③ For glutathione peroxidase,there was a significant interaction between food treatment and transportation time (P<0.05).Compared with the control group,the glutathione peroxidase activity in the plasma of broilers in the experimental group was significantly higher than that in the control group (P<0.05);Transport stress significantly affected the activity of glutathione peroxidase in the plasma of broilers in the control group.With the prolongation of transport time,the activity of glutathione peroxidase in the plasma of broilers decreased significantly (P<0.05).Therefore,transportation stress affected the metabolism level,hormone secretion and antioxidant function of Yellow feather broiler.Adding citrus extract to the diet could improve the metabolism level,regulate hormone secretion and improve antioxidant capacity,and alleviate the impact of transportation stress on Yellow feather broiler.     

Effects of food deprivation and particle size of ground wheat on digestibility of food components in broilers fed on a pelleted diet

The first aim of the experiment was to study the effect of wheat (Triticum aestivum) particle size on the digestibility of starch in a pelleted diet given to broilers. The second aim was to study the consequences of food deprivation before the excreta collection period (from 21 to 24 d). Wheat from a strong hardness cultivar was incorporated at 546.1 g/kg in diets. The other main ingredients were soybean meal (353.5 g/kg) and rapeseed oil (55.0 g/kg). Diets were given as pellets. The experimental design was a 2 x 2 factorial design testing two particle sizes of wheat flour and two procedures of a balance experiment (with or without food deprivation). Birds given diet C (wheat coarse grinding before pelleting) had significantly greater gizzard weight than birds fed on diet F (wheat fine grinding before pelleting). Starch digestibility value was significantly increased when birds were fed on diet F. This effect was halved by food deprivation. No significant effect of grain particle size was observed for protein and lipid digestibility values. However, food deprivation decreased apparent protein digestibility, with an effect which was more pronounced for fine than for coarse grinding. AMEN of the diet was significantly improved by fine grinding of wheat and decreased by food deprivation. However, no significant differences in growth performance were induced by differences in wheat grinding. No significant effect of grinding was observed on the water excretion:feed intake ratio. No significant difference was observed for vent score between treatments. There was over-excretion of starch in the first hours of refeeding following food deprivation.     

Growth performance and immune response of two commercial broiler strains fed diets containing Lactobacillus cultures and oxytetracycline under heat stress conditions

1. Hubbard x Hubbard (HH) and Shaver x Shaver (SS) chicks given a dietary supplement of either 50 mg/kg oxytetracycline (OTC) or 1 g/kg Lactobacillus culture (LC) were exposed to 36 +/- 1 degrees C for 3 h daily from day (d) 21 to 42. 2. Prior to heat treatment, body weight (d 21) and weight gain (d 1 to d 21) of OTC and LC birds were greater than those fed the control diet. Chicks given LC had the best food efficiency followed by OTC and control birds during d 1 to d 21. Body weight (d 1 and d 21) and weight gain (d 1 to d 21) were greater for HH tlhan SS chicks. 3. After 3 weeks of heat exposure, birds receiving the LC diet had greater body weight and weight gain, higher food intake and lower food efficiency than OTC and control chicks. 4. Antibody production against Newcastle discase vaccine on d 21 was not affected by strain or diet. On d 42, while diet had negligible effect on this variable among the SS broilers, HH birds fed LC had higher antibody production than those on the control diet. 5. Neither strain nor diet had a significant effect on mortality.     

Sequential feeding of whole wheat to growing broiler chickens

1. Four broiler feeding trials were performed to examine the suitability of a whole wheat sequential feeding regimen for commercial broiler production. The sequential feeding programme gave a continuous cycle of ad libitum access to only whole wheat followed by the same time of access to only a pelleted diet. The pelleted diet provided a concentration of nutrients to balance that provided by the whole wheat. This was called a balancer diet.

2. The first trial used 144 cage‐reared broilers from 28 to 49 d of age. Four different times of access (4, 8, 12 and 24 h) to the two alternate foods were compared. A whole wheat choice‐feeding treatment and a complete single diet treatment were also compared. Whole wheat accounted for over 40% of the broilers’ total food intakes when they were given the sequential feeding treatments of 8 h or greater. The whole wheat intakes of the birds given the 4 h sequential feeding and the choice‐feeding were only 20 and 5% respectively. There was a non linear relationship between the weight gains of the broilers and the length of the sequential feeding period (P< 0.01). The growth rates of the broilers given sequential feeding were lowest (P< 0.05) in the 4‐h feeding periods but highest (P< 0.05) in the 8‐h periods. Weight gains decreased (P< 0.01) linearly as the sequential feeding periods were increased above 8 h.

3. A second trial, using 144 cage‐reared broilers, examined the effect of different balancer compositions or different wheat varieties in 8‐h sequential feeding. The broilers selected more whole wheat in their diet when they were given balancers with increased cereal contents. However, these broilers did not eat enough whole wheat to compensate for the reduced cereal content of the balancers and their overall diets had lower energy: protein ratios. The two different wheat samples did not result in any differences (P> 0.05) in the proportion of whole wheat selected by the broilers.

4. A third trial compared the diet selections, weight gains, food intakes and water excretions of 72 cage‐reared broilers given whole wheat feeding regimens. The growth rates of the broilers given a loose mix of whole wheat and a pelleted balancer diet were similar (P> 0.05) to broilers given a complete single diet. The growth rates of these two groups were 7% greater (P< 0.05) than broilers given choice‐feeding or 8‐h sequential feeding. There were no differences (P> 0.05) in the total amounts of water excreted among the 4 treatments.

5. The fourth trial used 828 broilers distributed in 6 floor pens. They were given either a complete diet or an 8‐h whole wheat sequential feeding regimen from 25 to 46 d of age. The food intakes and the growth rates of the broilers were reduced (P<0–05) in die sequential feeding treatment by 9% and 5% respectively. There was no difference (P> 005) in litter moisture between the 2 treatments.     

蛋氨酸铬对肉鸡生长、脏器指数及血液生化指标的影响

试验旨在研究日粮中添加蛋氨酸铬对肉鸡生长、脏器指数及血清生化指标的影响,为确定日粮中蛋氨酸铬的适宜添加量提供科学依据。试验选用1日龄AA肉鸡528只,设4个处理,每个处理4个重复,每个重复33只。对照组饲喂玉米-豆粕型基础日粮,其它处理组饲喂分别在基础日粮中添加蛋氨酸铬0.1 mg/kg(Ⅰ组)、0.2 mg/kg(Ⅱ组)、0.6 mg/kg(Ⅲ组)的日粮(以Cr3+计),试验期49 d。结果表明:蛋氨酸铬能显著降低饲料消耗(P<0.05),但对肉鸡各日龄段平均体重、料重比和成活率影响差异均不显著(P>0.05)。除能显著降低心脏相对重量(P<0.05)外,日粮中添加蛋氨酸铬对肉鸡其它脏器相对重量影响差异均不显著(P>0.05)。日粮中添加蛋氨酸铬对血液生化指标影响显著(P<0.05)。因此,日粮中补充蛋氨酸铬对肉鸡生产性能、脏器指数影响不明显;但对血液生化指标影响显著,建议日粮中蛋氨酸铬添加量以0.2 mg/kg为宜。     

几种食材原料对肉鸡生长性能、胴体性状和体液免疫的影响

文章旨在探讨日粮单独或联合添加几种常用的生活食材对肉鸡生长性能、胴体性状和体液免疫的影响。试验将672只1日龄、平均体重为(40.04±0.01)g科宝肉鸡随机分为7组,每组4个重复,每个重复24只。对照组饲喂玉米-豆粕型基础日粮,T1~T6组分别饲喂基础日粮添加4g/kg黑胡椒、4g/kg姜黄、10g/kg香菜籽及4g/kg黑胡椒+4g/kg姜黄、4g/kg黑胡椒+10g/kg香菜籽、4g/kg黑胡椒+4g/kg姜黄+10g/kg香菜籽。结果:T5和T6组肉鸡在7和35d体重均显著高于对照组(P<0.05),在22~28d及1~35d时,处理组肉鸡料重比均显著低于对照组(P<0.05)。T6组肝脏和腺胃相对重量较对照组分别显著提高7.22%和40.63%(P<0.05)。T6组血清总蛋白和球蛋白含量均显著高于对照组(P<0.05),但葡萄糖、甘油三酯浓度及谷丙转氨酶和碱性磷酸酶活性均显著低于对照组(P<0.05)。T6组肉鸡21和35d时抗新城疫抗体滴度水平较对照组分别显著提高25.46%和49.56%(P<0.05)。结论:在本研究条件下,日粮添加黑胡椒、香菜籽和姜黄混合物可以改善肉鸡饲料效率,提高肝脏和腺胃相对重量,促进肉鸡体液免疫反应。     

枯草芽孢杆菌对肉鸡生长性能、抗氧化功能和肠道形态的影响

本试验旨在研究枯草芽孢杆菌对肉鸡生长性能、抗氧化功能和肠道形态的影响。选取1日龄雄性爱拔益加(AA)肉鸡420只,随机分为4组,每组7个重复,每个重复15只鸡。对照组饲喂基础饲粮,枯草芽孢杆菌组在基础饲粮中添加200 g/t枯草芽孢杆菌,杆菌肽锌组在基础饲粮中添加250 g/t杆菌肽锌,枯草芽孢杆菌+杆菌肽锌组在基础饲粮中添加200 g/t枯草芽孢杆菌和250 g/t杆菌肽锌。试验期42 d。结果表明,与对照组相比,饲粮中添加枯草芽孢杆菌显著提高了22~42日龄肉鸡的平均日增重(ADG)和血清丙二醛(MDA)含量(P<0.05),显著降低了1~21日龄肉鸡的ADG、平均日采食量(ADFI)及血清超氧化物歧化酶(SOD)活性和空肠隐窝深度(P<0.05)。饲粮中添加枯草芽孢杆菌和杆菌肽锌对22~42日龄肉鸡的料重比(F/G)、1~42日龄欧洲效益指数和肝脏MDA含量有显著交互作用(P<0.05)。综上所述,饲粮中添加200 g/t的枯草芽孢杆菌能提高22~42日龄肉鸡的生长性能,在一定程度上改善肉鸡空肠黏膜形态;饲粮中添加200 g/t的枯草芽孢杆菌和250 g/t的杆菌肽锌能够提高肉鸡的生长性能。     

水产下脚料对肉鸡生长性能、胴体性状及肠道健康的影响

文章旨在评估日粮添加不同水平的水产下脚料对肉鸡生长性能、胴体性状及肠道健康的影响.试验将504只体重一致的1日龄肉鸡随机分为3组,每组6个重复,每个重复28只.对照组饲喂基础日粮,处理组饲喂水产下脚料添加水平为8％和16％的日粮,对照组与处理组日粮的营养水平保持一致,试验为期6周.结果:T1和T2组42?d肉鸡体重、2...     

The effects of dietary flax oil and antioxidants on ascites and pulmonary hypertension in broilers using a low temperature model

1. Three experiments were conducted using a low temperature model to induce pulmonary hypertension (PH) and ascites in broiler chickens. Diets containing 25 g or 50 g flax oil/kg food and control diets with an equivalent amount of animal/vegetable (A/V) blend oil, with and without supplemental antioxidants (vitamin C and vitamin E) were used. The amount of PH was assessed by the ratio of right ventricle weight to total ventricle weight (RV/TV ratio). Birds were considered to suffer from pulmonary hypertension syndrome (PHS) if the RV/TV ratio was greater than 0.299. 2. In experiment 1, the test diets contained 50 g oil/kg food and were given during the grower period only. Birds fed on the flax oil diet tended to have a lower incidence of PHS, ascites and lower RV/TV ratios than birds fed on the control diet. However, when the flax oil diet was supplemented with antioxidants, the incidence of ascites, PHS, haematocrit and whole blood and plasma viscosity increased compared with birds fed on the flax oil diet without antioxidants. These effects were not seen in experiment 2, when the test diets containing 30 g oil/kg food (25 g flax oil plus 5 g A/V blend oil/kg food compared to 30 g A/V blend oil/kg food) were given during the grower period. However, in experiment 3, when the test diets containing 30 g oil/kg food were given from day 1 to week 8, birds fed on the control diet supplemented with antioxidants had a higher incidence of PHS than those fed on the control diet alone. 3. In all 3 experiments, there was no significant effect of dietary fat source or supplemental antioxidants on total food intake or food conversion. 4. We conclude that diets containing 50 g flax oil/kg food tend to reduce the incidence of PHS and ascites in broilers using a low temperature model but the results were not statistically significant. In some cases, supplementing diets with a combination of vitamin E and vitamin C increased the incidence of ascites and PHS.     

不同类型昆虫粉对肉鸡生长性能、血液生化指标及肠道发酵的影响

本研究旨在评估昆虫粉对肉鸡生长性能、血液生化指标及肠道发酵的影响。试验将432只1日龄商品肉鸡分为3组,每组6个重复,每个重复24只。各组肉鸡分别饲喂基础日粮（对照组）、基础日粮+0.5%黄粉虫粉（黄粉虫组）和基础日粮+0.5%水虻粉（水虻组）,饲养试验为期4周。结果：对照组15～28?d肉鸡料重比较黄粉虫和水虻组分别显著提高8.10%和4.13%（P＜0.05）,对照组1～28?d肉鸡料重比较黄粉虫组显著提高5.35%（P＜0.05）。黄粉虫和水虻粉组肉鸡血清白蛋白和磷浓度显著高于对照组（P＜0.05）,但胆固醇浓度显著降低（P＜0.05）。黄粉虫组肉鸡血清GOT活性显著低于对照组和水虻粉组（P＜0.05）。水虻粉组血清MDA浓度显著低于黄粉虫组（P＜0.05）,但血清SOD活性表现最高（P＜0.05）。对照组肉鸡盲肠α-葡萄糖苷酶和β-半乳糖酶活性显著高于水虻粉组（P＜0.05）,而β-葡萄糖苷酶活性显著高于黄粉虫组（P＜0.05）。对照组盲肠内容物乙酸、丙酸和挥发性脂肪酸总量浓度显著高于处理组（P＜0.05）。结论：1～28?d肉鸡日粮中补充0.5%黄粉虫可以改善饲料效率,降低血清胆固醇浓度,而0.5%水虻粉可以提高肉鸡血清抗氧化功能。 [关键词]昆虫粉|肉鸡|生长性能|血液生化|肠道发酵     

Intestinal morphology, brush border and digesta enzyme activities of broilers fed on a diet containing Cu2+-loaded montmorillonite

1. A total of 320 1-d-old Arbor Acres broiler chicks were used to investigate the effect of Cu(2+)-loaded montmorillonite (CM) on the growth performance, intestinal morphology and activities of brush border enzyme in the intestinal mucosa and digestive enzyme in the intestinal digesta of broilers. 2. The chicks were assigned randomly into 4 groups with 80 chicks per treatment. The 4 dietary treatments were: basal diet only (control group), basal diet + 2 g montmorillonite/kg, basal diet + 1 g CM/kg, and basal diet + 2 g CM/kg. The chicks were raised in cages and feed and water were provided ad libitum for a period of 42 d. 3. The addition of CM to the diet of broilers significantly increased body weight and feed efficiency. Similarly, birds receiving montmorillonite had higher feed efficiency than the control after 42 d of feeding. 4. Data on villus height and crypt depth for duodenum, jejunum and ileum indicated that treating the diet of broilers with either CM or montmorillonite improved the mucosal morphology of the small intestine. 5. The presence of CM in the diet of broilers significantly increased the activities of maltase, aminopeptidase N and alkaline phosphatase in small intestinal mucosa. However, the activities of protease, trypsin, chymotrypsin, amylase and lipase in small intestinal digesta of broilers fed on the CM-supplemented diet were slightly higher than control values.     

苜蓿素对AA肉仔鸡免疫指标的影响

为研究不同剂量的苜蓿素对AA肉仔鸡免疫指标的影响,选取1日龄AA肉仔鸡120只,随机分为4组,对照组饲喂基础日粮,试验Ⅰ~Ⅲ组基础日粮中分别添加150、300、450 mg/kg苜蓿素。分别于28、35和42 d从每组取10只鸡进行采血,测定血清球蛋白含量;取法氏囊和脾脏,称重并计算免疫器官指数;采用MTT比色法测定T、B淋巴细胞增殖能力。结果表明,基础日粮中添加300 mg/kg苜蓿素饲喂28 d,能够显著提高AA肉仔鸡法氏囊指数（P〈0.05）;添加450 mg/kg苜蓿素饲喂28 d,能够显著提高AA肉仔鸡血清球蛋白含量和免疫器官指数（P〈0.05）。添加300 mg/kg苜蓿素饲喂35 d,能够显著提高AA肉仔鸡血清球蛋白含量、免疫器官指数（P〈0.05）,显著促进B淋巴细胞增殖（P〈0.05）;添加450 mg/kg苜蓿素饲喂35 d,能够显著提高血清球蛋白含量、脾脏指数（P〈0.05）,显著促进T淋巴细胞增殖（P〈0.05）,极显著促进B淋巴细胞增殖（P〈0.01）。添加300和450 mg/kg苜蓿素饲喂42 d,能够极显著提高AA肉仔鸡法氏囊指数（P〈0.01）;添加450 mg/kg苜蓿素饲喂42 d,能够显著促进B淋巴细胞增殖（P〈0.05）。结果提示,日粮中添加苜蓿素能够提高多项AA肉仔鸡免疫指标,以添加450 mg/kg效果最优。     

乳酸菌培养物对肉鸡生长性能及免疫功能的影响

试验旨在研究灭活乳酸菌培养物对肉鸡生长性能及免疫功能的影响。选择300只体重相近的健康1日龄AA肉仔鸡,随机分为5组,每组6个重复,每个重复10只鸡,雌、雄各半。其中对照组饲喂基础日粮,抗生素组在基础日粮中添加0.01%金霉素,乳酸菌培养物组分别在基础日粮中添加0.16%乳酸菌培养物L1、L2、L3。试验期42 d,分1~21日龄(前期)和22~42日龄(后期)2个阶段。结果显示,1~21日龄时,乳酸菌培养物L1组肉鸡平均日采食量极显著高于对照组和抗生素组(P<0.01),血清中白介素-2(IL-2)含量显著低于对照组(P<0.05),脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L2组肉鸡脾脏指数、胸腺指数显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);抗生素组肉鸡血清中γ-干扰素(IFN-γ)含量显著高于乳酸菌培养物组(P<0.05)。22~42日龄时,乳酸菌培养物L1、L2组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);乳酸菌培养物L2组肉鸡血清中免疫球蛋白G(IgG)含量显著高于抗生素组(P<0.05),血清新城疫抗体效价及脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡血清中免疫球蛋白A(IgA)含量及胸腺指数显著高于对照组(P<0.05)。由此可知,在肉鸡日粮中添加一定量的灭活乳酸菌培养物可在一定程度上提高肉鸡的生长性能、增强其免疫功能,其中,对于提高肉鸡的生长性能,试验前期添加L3效果较好,试验后期添加L1和L2效果较好;对于增强肉鸡的免疫功能,试验前期添加L1效果较好,试验后期添加L2效果较好。     

液体纳米维生素对肉仔鸡生产性能和胴体品质的影响

试验选用480只1日龄健康艾维茵肉仔鸡。随机分为4组,每组设4个重复,每个重复30只。对照组饲喂基础日粮,3个试验组分别给予含液体纳米维生素4000、6000、8000倍稀释液的饮水。试验期为42d。试验旨在研究液体纳米维生素对肉仔鸡生产性能和胴体品质的影响。结果表明,液体纳米维生索能显著提高肉仔鸡的平均日增重、饲料利用率和出栏重（P〈0．01）,可显著降低肉仔鸡均日采食量和死亡率（P〈0．01）;屠宰试验测定表明,液体纳米维生素可显著提高肉仔鸡半净膛率、全净膛率、胸肌率和腿肌率（P〈0．01）,对屠宰率也有一定影响,但差异不显著（P〉0．05）。因此,液体纳米维生素能显著提高肉仔鸡的生产性能以及改善胴体品质．且较高水平的液体纳米维生素会产生较好的生产效率     

苜蓿多糖对不同性别肉仔鸡生长性能、屠宰性能、肉品质及抗氧化性能的影响

本试验旨在研究苜蓿多糖对不同性别肉仔鸡生长性能、屠宰性能、肉品质及抗氧化性能的影响。选取468只1日龄爱拔益加(AA)肉仔鸡,随机分为3组,每组12个重复(公母各6个重复),每个重复13只鸡。组1为对照组,饲喂基础饲粮,组2、组3分别在基础饲粮中添加1 000和2 000 mg/kg苜蓿多糖,试验期42 d。结果表明:与对照组相比,1)饲粮中添加1 000和2 000 mg/kg苜蓿多糖对公鸡和母鸡的平均体重、平均日采食量、平均日增重、料重比、屠宰率、腿肌率和腹脂率均无显著影响(P0.05),但显著提高了母鸡全净膛率和胸肌率(P0.05),且添加2 000 mg/kg苜蓿多糖显著提高了公鸡胸肌率(P0.05)。2)1 000 mg/kg苜蓿多糖组(即组2)公鸡胸肌p H45 min显著提高(P0.05),公鸡和母鸡胸肌滴水损失率和公鸡胸肌蒸煮损失率显著降低(P0.05);2 000 mg/kg苜蓿多糖组(即组3)公鸡和母鸡胸肌滴水损失率和公鸡胸肌蒸煮损失率显著降低(P0.05)。1 000 mg/kg苜蓿多糖组公鸡和母鸡腿肌滴水损失率和母鸡腿肌剪切力显著降低(P0.05),母鸡腿肌p H24 h显著提高(P0.05);2 000 mg/kg苜蓿多糖组母鸡腿肌滴水损失率和剪切力显著降低(P0.05)。3)1 000和2 000 mg/kg苜蓿多糖组21日龄公鸡血清总抗氧化能力(T-AOC)显著提高(P0.05),2 000 mg/kg苜蓿多糖组35和42日龄母鸡血清T-AOC显著提高(P0.05),2 000 mg/kg苜蓿多糖组28日龄公鸡和母鸡血清谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(P0.05),1 000和2 000 mg/kg苜蓿多糖组21和35日龄母鸡血清总超氧化物歧化酶(T-SOD)活性显著提高(P0.05),但饲粮中添加1 000和2 000 mg/kg苜蓿多糖对公鸡和母鸡血清中丙二醛(MDA)含量无显著影响(P0.05);此外,饲粮中添加1 000和2 000 mg/kg苜蓿多糖对公鸡和母鸡肝脏和胸肌中T-AOC、GSH-Px和T-SOD活性及MDA含量均无显著影响(P0.05)。综上,饲粮中添加苜蓿多糖对公鸡和母鸡的生长性能无显著影响,但能够改善公鸡和母鸡的屠宰性能、肉品质和血清抗氧化性能,且苜蓿多糖的适宜添加量为1 000mg/kg。     

饲粮菊糖添加水平对肉仔鸡盲肠、直肠菌群结构及主要菌群数量的影响

本试验旨在研究饲粮菊糖添加水平对肉仔鸡盲肠和直肠菌群结构和主要菌群数量的影响。采用单因素完全随机化设计,选用300只1日龄爱拔益加肉仔鸡,随机分成5组,每组6个重复,每个重复10只。5组肉仔鸡分别饲喂在基础饲粮中添加0(对照组)、0.5、1.5、2.5和5.0 g/kg菊糖的试验饲粮。试验期为6周。采用PCR-变性梯度凝胶电泳(DGGE)和定量PCR(q PCR)技术对42日龄肉仔鸡盲肠和直肠菌群结构及主要菌群数量进行测定。结果表明:1)饲粮菊糖添加水平对肉仔鸡盲肠和直肠菌群丰富度、盲肠菌群香农指数以及直肠菌群均匀度均无显著影响(P0.05),但显著降低了盲肠菌群均匀度和直肠菌群香农指数(P0.05)。PCRDGGE图谱上部分优势条带序列分析表明,饲粮添加菊糖促进了肉仔鸡盲肠和直肠厚壁菌门(Firmicutes)中产粪甾醇真细菌(Eubacterium coprostanoligenes)、肠单胞球菌(Intestinimonas sp.)和盲肠肠球菌(Enterococcus cecorum)等细菌的增殖。2)饲粮菊糖添加水平显著影响了肉仔鸡盲肠、直肠总细菌和大肠杆菌数量(P0.05)。二次曲线分析显示,当菊糖添加水平分别为2.71和2.66 g/kg时,盲肠总细菌和大肠杆菌数量最少;与对照组相比,饲粮添加1.5、2.5、5.0 g/kg菊糖显著降低了盲肠乳酸菌数量(P0.05),饲粮添加0.5 g/kg菊糖显著增加了直肠乳酸菌数量(P0.05);饲粮添加5.0 g/kg菊糖时肉仔鸡盲肠、直肠双歧杆菌数量及直肠产气荚膜梭菌数量均为最高,且与对照组差异显著(P0.05)。综上,在本试验条件下,有利于改善肉仔鸡肠道菌群结构和促进有益菌增殖的菊糖添加水平为2.5~5.0 g/kg。     

丁酸甘油酯对肉鸡生长性能、养分表观消化率、屠宰性能、肠道形态及微生物菌群的影响

试验旨在研究丁酸甘油酯对肉鸡生长性能、养分表观消化率、屠宰性能、肠道形态及微生物菌群的影响。选用1日龄罗斯308肉鸡384羽,随机分为4组,每组4个重复,每个重复24羽。对照组饲喂基础日粮,试验组在基础日粮中添加250、500、750 g/t剂量的丁酸甘油酯替代40%的油脂饲喂,试验周期为42 d。结果显示,与空白对照组相比,饲料中添加丁酸甘油酯对于肉鸡的生长性能具有促进作用,其中中剂量组（500 g/t）添加效果最好。各剂量组肉鸡屠宰性能较空白对照组有所改善,但差异不显著（P>0.05）;与空白对照组相比,各剂量组十二指肠和空肠肠绒毛高度均有所提高,其中中剂量组与对照组差异显著（P<0.05）,各剂量组隐窝深度有变浅的趋势,但差异不显著（P>0.05）;与空白对照组相比,中剂量组的粗脂肪和粗纤维表观消化率均显著提高（P<0.05）;大肠杆菌数量显著减少（P<0.05）,盲肠乳酸菌数量显著增加（P<0.05）。综上所述,基础日粮添加丁酸甘油酯能促进生长性能,提高饲料养分消化率,改善肠道形态和微生物菌群,肉鸡日粮中丁酸甘油酯最佳添加剂量为500 g/t。     

1～21日龄岭南黄羽肉仔鸡饲粮硒适宜供给量的研究

本试验旨在研究饲粮不同硒添加水平对1~21日龄岭南黄羽肉仔鸡生长性能和抗氧化性能的影响,以探讨快大型岭南黄羽肉仔鸡饲养前期的饲粮硒适宜供给量。选用1日龄健康、发育良好的快大型岭南黄羽肉公雏鸡1 200只,根据体重随机分为5个组,每组6个重复,每个重复40只鸡,试验1组(对照组)饲喂基础饲粮(硒水平为0.039 mg/kg),试验2~5组饲粮在基础饲粮中分别添加0.075、0.150、0.225和0.300 mg/kg硒,试验期21 d。结果表明:本试验条件下:1)与对照组相比,饲粮添加0.300 mg/kg硒显著降低1~21日龄岭南黄羽肉仔鸡的末重(P0.05),显著提高料重比(P0.05),且0.300 mg/kg硒添加组的平均日增重显著低于其他各水平硒添加组(P0.05)。2)与对照组相比,饲粮添加0.075和0.150 mg/kg硒显著提高21日龄岭南黄羽肉仔鸡的血浆谷胱甘肽过氧化物酶(GSH-Px)活性(P0.05),饲粮添加0.225和0.300 mg/kg硒显著降低血浆丙二醛(MDA)含量(P0.05)。各水平硒添加组的红细胞GSH-Px活性均显著高于对照组(P0.05)。3)与对照组相比,饲粮添加0.075、0.150和0.225mg/kg硒显著提高21日龄岭南黄羽肉仔鸡的肝脏GSH-Px活性(P0.05),0.075和0.150 mg/kg硒添加组的肝脏MDA含量显著低于对照组和0.300 mg/kg硒添加组(P0.05)。综合考虑,为获得较好生长性能和抗氧化性能,1~21日龄岭南黄羽肉仔鸡饲粮硒适宜添加水平为0.075 mg/kg,基础饲粮中硒水平为0.039 mg/kg,则1~21日龄岭南黄羽肉仔鸡饲粮硒适宜供给量为0.114 mg/kg;以肝脏MDA含量为依据,通过非线性回归分析估测得到1~21日龄岭南黄羽肉仔鸡饲粮硒适宜供给量为0.130 mg/kg。