蛋氨酸的生物学功能及其在鸡日粮中的应用

本文就蛋氨酸的生物学功能及其在鸡日粮中的应用作一综述。

日粮中不同蛋氨酸水平对蛋品质的影响

当前,蛋壳破损仍是一个严重的问题,给生产者和经营者造成的经济损失是惊人的。据报道,因蛋壳破损加拿大每年损失达600万美元,美国达70—159.2百万美元,澳大利亚达370万美元,英国达1500万英磅,苏联达20亿枚蛋,巴西达1500万英磅。日本是世界上屈指可数的鸡蛋消费国,年消费量约200万吨,价值达6000亿日元,而它的破蛋率为6.39(4—12.15)％。最近调查笼养鸡的破蛋率为7％。兰州市肉联厂利用冷库破损蛋生产的蛋壳粉每年有5吨,以每枚蛋壳重5—6克计,该厂每年破蛋约83—100万枚。兰州鸡场由鸡舍拣出的破蛋率为4.92％(未包括鸡舍内的破损蛋),而从鸡场直接运到用户手中的破蛋率约12.46％,由此可以想象,全国乃至世界的破蛋所造成的经济损失。为此,许多国家的畜牧工作者,从遗传育种。

Ensiled Cassava Peel and Caged Layers＇ Manure Mixture as Energy Source in Broiler Starter Diet

The replacement of maize with dried cassava peel and dried caged layers＇ manure mixed in ratio 5：1 （w/w）, ensiled for 14 days was investigated in broiler starter diet to evaluate their growth responses. The fermented mixture was used to partially replace maize at 0, 25% and 50% in broiler starter diet. Ninety （90） day old chicks, of Anark breed were divided into three groups of three replicates each. There were ten birds per replicate and each group was fed each of the dietary treatment ad libitum for 28 days. Feed intake, body weight gain, feed conversion ratio （FCR）, protein efficiency ratio （PER）, total protein, albumin, globulin, aspartate aminotransaminase （EC 2.6.1.1.1）, alanine aminotransaminase （EC 2.6.1.1.2）, carcass cut parts and cost per kilogram flesh gained were monitored. Results showed linear increase （P 〈 0.05） in feed intake, body weight gain, FCR, and PER. The serum proteins and enzymes monitored were not influenced （P 〉 0.05） by treatments. The eviscerated weight, wings and large intestine length were higher （P 〈 0.05） in birds fed 50% replacement of maize diet. The cost of feed per kilogramme and cost per kilogramme flesh gained was best （P 〈 0.05） in birds fed diets 50% replacement of maize. Therefore, fermented mixture of cassava peel and caged layers＇ manure （FCPCLM） in broiler starter diet at 50% dietary level support good performance, enhanced gain in eviscerated weight and reasonable cost per kilogramme flesh gained at the starter phase.

Effect of Thermal Processing, Press Throughput and Roller-Die Gap on Physicochemical Properties of Broiler Feed Pellets

The present study aimed to evaluate the effect of thermal processing, press throughput and roller-die gap on pellet physical quality, protein solubility and starch gelatinization in a corn-soybean based broiler diet. The different processing factors were combined in a 2 × 5 × 3 factorial arrangement with eight randomized block consisting of eight production series： two thermal processing treatments （conditioning-pelleting or conditioning-expanding-pelleting）, five press throughput levels （18, 21, 24, 27 and 30 ton/h） and three roller-die gap （0.50, 0.75 and 1.00 mm）, which resulted in 30 different processed feeds. For determination of pellet durability index （PDI）, amount of intact pellets, degree of starch gelatinization and protein solubility, one composed feed sample was collected per treatment in each of eight production series, totaling eight replicates per treatment. Data concerning the amount of intact pellet and protein solubility in KOH were transformed using a variation of Box-Cox transformation in order to fit a normal distribution （P 〉 0.05）. Pellet physical quality was enhanced by conditioning-expanding treatment （P 〈 0.01）, narrower roller-die-gap （P 〈 0.01） and reduced press throughput （P 〈 0.01）. Protein solubility in KOH was impaired （P 〈 0.01） in the expander treatment and larger roller-die distance （0.75 mm and 1.00 mm） （P 〈 0.01）. Finally, greater starch gelatinization degree was achieved in expanded treatment （P 〈 0.01） and in 1.00 mm roller-die gap （P 〈 0.05）. The factors evaluated in this study resulted in interactions and significant effects on physicochemical properties of broiler feed pellets.

The Effect of the Supplemental Different Levels of Anise Seeds （Pimpinella anisum） in Diet on Broiler Performance

This experiment was conducted at the poultry farm, poultry research station, state board of agriculture research, ministry of agriculture to study the effect of supplemental anise seed on broiler diets. A total of 640 of one-day old unsexed broiler chicks （Cobb） were used in this study. They were randomly distributed to four treatments. Anise seeds were supplemented at the levels of 0.2%, 0.4% and 0.6% compared with the control group for 49 days. The results showed： there was a significant （P 〈 0.05） increase in the rate of body weight for the two treatments 0.6% and 0.4% of the anise seeds compared with 0.2% and control treatments, body weight gain take the same direction, like in body weight, the highest treatment was 0.6% followed by treatment 0.4% as well as the feed consumption has increased in these treatments than in 0.2% and control treatments, so about feed conversion ratio the treatment 0.6% of the anise seeds recorded the best feed conversion ratio compared with other treatments. Significant decreased in mortality and significant increased in production index by increasing the level of anise seeds in feed. Dressing percentage increased significantly for all treatments using anise seeds and treatment 0.6% recorded highest dressing percentage, from the other hand percentage of abdominal fat decreased significantly by increasing anise seed levels and no significant difference in the percentages of liver, gizzard and heart were recorded in this study. About carcass cuts, the weights of primary cuts （thigh, drum stick, breast） relative to body weight recorded significant increase in the treatments using anise seeds at the expense of secondary cuts （neck, wings, back）. There was a significant decline （P 〈 0.05） for total bacterial （E. coli and Staphylococci） in small intestine in all level of anise seeds （0.2%, 0.4%, 0.6%） in ration while the decline of two types of bacteria in colon recorded in 0.4% and 0.6% treatments compared with 0.2~/0 and control treatments. Conclude from this study the possibility of using anise seeds at all levels used in the experiment and the best level that can be used to get the best performance of the positive results of broiler chickens is 0.6%.

Metabolizable Energy and Amino Acid Bioavailability of Field Pea Seeds in Broilers Diets

The aim of this study was to determine the apparent （AME） ＆ true （TMEn） metabolizable energy as well as the crude protein （CP） ＆ amino acid （AA） total tract （by excreta collection） digestibility （bioavailability） of field pea seeds （FPS） of the Greek cultivar ＂Olympos＂. Forty eight broilers were placed in individual cages and randomly allocated into 4 dietary treatments. Birds consumed 80 g/d of either a typical commercial diet or the same diet in which 100, 200 or 300 g/kg had been substituted by ground FPS. The experiment lasted 15 d. Apparent and true CP bioavailability of FPS were significantly decreased （P 〈 0.05） only at the inclusion rate of 300 g/kg. AA bioavailability remained at high levels （-0.80）, with the exception of methionine and valine and was similar to CP mean. The mean AME and TMEn values of FPS were estimated equal to 10.8 and 11.0 MJ ME/kg, respectively.

Effect of Dietary Nitrogen Corrected-True Metabolism Energy and Digestible Amino Acids on Broiler Breeder Reproductive Performance

A study was conducted to determine the effects of dietary digestible amino acids of feedstuffs and true metabolizable energy corrected for nitrogen on broiler breeder performance in 50 weeks to 64 weeks of age. 140 females and 20 males broiler breeders in 4 treatments with 5 replicates （7 females with a male） were used in the form of a completely randomized trial design 2 ~ 2 factorial. Four experimental diets were formulation based on two factors, first factor was included, two types of Apparent and True Metabolizable Energy corrected for Nitrogen （AMEn and TMEn） and the second factor was included, two types of Total Amino Acids （TAA） and Digestible （DAA） of feedstuffs. The result showed that egg weight, egg production （%） and egg mass （g/hen/day） was significantly different which was affected by diets formulation based on energy and interaction between energy and amino acids （P 〈 0.01）. Treatment 2 （AMEn ＋ DAA） was at the highest level significantly different （P 〈 0.01） in egg weight 68.97 g, egg production 62.45%, and egg mass 43. i g/hen/day. Hatching eggs were significantly different which was affected by diet formulation based on amino acids. Fertility, hatchability and number of chicks per hen were significant different, that were affected by diet formulation based on energy （P 〈 0.05）. Interaction between two factors, were significantly different in two reproductive traits fertility and hatchability （P 〈 0.05）. This experiment showed that diet formulation based on AMEn and DAA for broiler breeder was better and significant on performance.

复合酸化剂对肉仔鸡生产性能的影响

本试验选用132只1日龄AA肉仔鸡随机分为3组,每组设4个重复,每个重复11只鸡,一组饲喂基础日粮作为对照组,另两组在基础日粮中添加0.5%和1.0%复合酸化剂作为试验组,研究日粮中添加复合酸化剂对肉仔鸡体增重和屠宰性能的影响,确定肉鸡日粮中适宜的复合酸化剂添加量。试验分两个阶段,前期0～21日龄,后期22～42日龄,每个阶段始末称重。试验结果表明,肉鸡日粮中添加0.5%、1.0%复合酸化剂不同程度改善肉鸡各阶段的体增重、料重比和成活率;但对肉鸡屠宰性能没有显著影响,综合指标来看,肉仔鸡日粮添加1.0%复合酸化剂的作用效果最佳。