甜菜碱对生长猪增重和胴体组成影响的性别差异及机理

６０头约２０ ｋｇ的杜长大三元杂交猪（Ｄｕｒｏｃ×Ｌａｎｄｒａｃｅ×Ｙｏｒｋｓｈｉｒｅ）随机分成２个处理组，即对 照组和试验组，每个处理有３个重复组，每个重复１０头（阉公猪、母猪各半），对照组饲喂不含甜菜碱的 饲粮，试验组饲喂含１５００ ｍｇ／ｇ甜菜碱的饲粮，试验猪结束体重约为６５ｋｇ。从试验组和对照组中各挑 选体重相近的阉公猪、母猪各６头进行屠宰试验，结果表明：饲喂甜菜碱使阉公猪、母猪的日增重分别达 １０．３０％和１５．６３％、提高瘦肉率３．０１％和８．２０％，提高母猪的眼肌面积３９．２１％；而阉公猪、母猪的背 膘厚分别降低１８．１２％和１０．８３％。血清中激素水平测定结果还显示，甜菜碱可提高阉公猪、母猪的ＧＨ 含量６２．５０％和７０． ９７％、ＩＧＦ－Ｉ含量７４．３３％和４４． ９８％，且未见性别差异。肌肉样品测定结果表明，甜 菜碱明显提高了阉公猪背最长肌酸不溶肉碱的含量（４１．２６％），但对母猪背最长肌酸不溶肉碱的含量 未产生显著影响。结果显示：甜菜碱对２０～６５ ｋｇ生长猪的增重和胴体组成的影响上存在着性别差异， 在降低背膘厚的效果上，阉公猪优于母猪。这说明甜菜碱作为甲基供体，能更有效地促进阉公猪体内肉 碱的合成，

Effect of feeding betaine on weight-gain and carcass trait of barrows and gilts and approach to mecha-nism

sixty pigs (Duroc X Landrace X Yorkshire , 20 kg initially) were allotted to two treatments (Con- trol and Control 1500 mg/kg betaine ) set with three replicate pens per treatments by weight and sex. There were 5 barrows and 5 gilts each replicate. Twelve pigs (6 barrows, 6 gilts) per treatments were slaughted when final weight was about 65 kg . The sample of serum ,liver and muscle were taken to analy- sis. The results showed that betaine supplementation increased average daily gain (ADG) of barrow and gilts by 10. 30% and 15. 63% respectively , increased percentage of dissected lean of carcass (PDL) by 3. 01% and 8. 20% respectively, increased longissimus dorsi area (LDA) of gilt by 39. 21%. Feeding be- taine decreased backfat of barrow and gilt by 18. 12 % and 10. 83%. The serum analysis indicated that be- taine supplementation increase the GH level of barrow and gilt by 62. 50% and 70. 97% , increased the IGF-1 level by 74. 33% and 44. 98% respectively. There was not sex differences. The data from muscle and liver sample analysis showed that feeding betaine significantly increased the content of free carnitine in liver (30. 29% ) , and the content of acid-insoluble carnitine in muscle (41. 26% ) , to barrow , but not to gilt . The results indicated there existed sex difference about effect of betaine on weight-gain and carcass trait in growing pigs . It was obvious that the effect on barrows were better in decreasing backfat. It indi- cated that betaine supplementation can effectively reduce the lipid deposition and exert the repartition ef- fects of the carcass fat , by donating the methyl to produce carnitine to improve the long chain fatty acid- oxidation in barrows. It was also obvious that the effect on gilt were better in increasing the ADG , LDA and PDL.