色氨酸对5～10周龄扬州鹅生长性能和屠宰性能的影响

选用270只21日龄的扬州公鹅,随机分成6组,每组3个重复,每个重复15只鹅。采用2×3二因子试验设计,采用两种饲喂方式(自由采食和90%限制饲喂,限制饲喂组鹅饲料供给量为前一天自由采食组饲料消耗量的90%)和低、中、高3个色氨酸(Trp)水平(含量分别为0.14%,0.22%和0.30%),分别对3个不同生长阶段的生长性能和屠宰性能指标进行测定。结果表明,在28～42日龄,与低、高Trp组相比,中Trp组扬州鹅平均日采食量和平均日增重显著提高(P<0.05),饲喂方式和Trp水平对扬州鹅平均日采食量、平均日增重和饲料转化率有交互作用(P<0.05);在42～56日龄,自由采食组扬州鹅平均日采食量和饲料转化率极显著高于限制饲喂组(P<0.01),平均日增重显著高于限制饲喂组(P<0.05)。与低、高Trp组相比,中Trp组扬州鹅平均日采食量显著提高(P<0.05),Trp水平对平均日增重和饲料转化率无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅平均日采食量有交互作用(P<0.05);在56～70日龄,Trp水平对扬州鹅平均日采食量、平均日增重和饲料转化率均无显著影响(P>0.05)。饲喂方式和Trp水平对扬州鹅平均日增重和饲料转化率有交互作用(P<0.05);在28～70日龄,自由采食组扬州鹅平均日采食量和平均日增重极显著高于限制饲喂组(P<0.01)。与低、高Trp组相比,中Trp组扬州鹅平均日采食量和平均日增重显著提高(P<0.05),而Trp水平对饲料转化率无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅平均日采食量和平均日增重有交互作用(P<0.05)。自由采食组扬州鹅全净膛率、胸肌率和腹脂率显著高于限制饲喂组(P<0.01),随着Trp水平的增加,扬州鹅胸肌率显著增加(P<0.01),而Trp水平对其他屠宰性能指标无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅腹脂率有交互作用(P<0.01)。由此可知,饲粮中Trp水平过低或过高均会对扬州鹅生长性能产生不利影响,并且这种不利的影响具有阶段性,因此日粮添加适当水平的Trp能够一定程度改善扬州鹅生长性能。

A total of two hundred and seventy geese were randomly allocated to 6 groups with 3 replications of 15 each in a 2×3 factorial design.Treatments consisted of two feeding regimens （ad libitum feeding VS 90 % feed restriction based on ad libitum intake of the previous 24 h）,each contained three levels of Trp （Low group 0.14 % ,Medium group 0.22 %, High group 0.30 % ）to which 0.08 % increments of tryptophan were supplied.Indices of three-phase growth per-formance and carcass characteristics were measured. The results showed that：during 28 to 42 days of age,the average dai- ly food intake （ADFI）and average daily gain （ADG）of greese of medium group were increased significantly compared with low and high group （P 〈 0.05）.There were interactions in ADFI,ADG and feed conversion rate （FCR） of goose between feeding regimen and dietary Trp level （P 〈 0.05）.During 42 to 56 days of age,the ADFI and FCR of goose of ad libitum feeding group were significantly higher than those of restricted feeding group （P 〈 0.01）,the same to ADG （P 〈 0.05）. Compared with low group and high group ,ADFI of groose medium was significantly increased （P 〈 0.05 ）,while no statisti-cal difference was found in ADG and FCR （P 〉 0.05 ）.And an interaction was observed in ADFI between feeding regimen and dietary Trp level （P 〈 0.05）.During 56 to 70 days of age, dietary Trp supplementation level had no significant effect on ADFI,ADG and FCR （P 〉 0.05）.Interactions were observed in ADG and FCR between feeding regimen and dietary Trp level（P 〈0.05）.During 28 to 70 days of age,ADFI and ADG of groose of ad libitum feeding group were significantly high-er than those of restricted feeding group （P 〈 0.01 ）.The ADFI and ADG of groose were significantly enhanced in medium group compared with other groups（P 〈 0.05）,while no statistical difference was found in FCR（P 〉 0.05）.There were inter-actions in ADFI and ADG between feeding regimen and dietary Trp level （P 〈 0.05）.The percentage of eviscerated car-cass,breast and abdominal fat was significantly increased of ad libitum feeding group （P 〈 0.01 ）.With the increase of di-etary Trp level,the percentage of breast of groose was increased significantly （P 〈 0.01 ）,while indices of other slaughterperformance were not significantly affected（P 〉 0.05）.An interaction was observed in percentage of abdominal fat betweenfeeding regimen and dietary Trp level （P 〈 0.01 ）.The results indicated that,too high or too low level of dietary Trp couldhave negative effects on growth performance of Yangzhou goose and the adverse impacts varied in different phases.Appro-priate supplementation of Trp to diet could increase growth performance of goose.