Effects Of Limiting Amino Acids On Hepatocyte IGF-ⅠmRNA Expression And Serum Biochemical Indexes Of Growing Goat Fed With A Basal Corn Stover

The study was conducted to test the effects of limiting amino acids on hepatocyteIGF-I mRNA expression and biochemical indexes of growing goat fed with a based cornstover diet.Three Liu-yang Black goats (10.00± 0.15 kg), fitted with ruminal, duodenal andileal cannula and fed a practical diet were used to determine infusive amounts of limitingamino acids in the duodenum which could be satisfied with the ideal amino acid pattern ofmusle. Results showed thatthe infusive amounts of the first, second and third limiting aminoacids in the duodenum were 0.77g/d (Met),0.91g/d (Lys) and 0.58g/d (Leu) respectively. Twelve Liu-yang Black goat (initial weight10.00± 0.23kg), cannulated in duodenum,were randomized to separate into 4 groups, three goats per group. All animals were put intothe metabolic cages respectively and free to fresh water. The four groups are as follows: A(removing 21%Met from the mixture of Met, Lys and Leu), B (removing 21% Lys from themixture of Met, Lys and Leu),C, (removing 21%Leu from the mixture of Met, Lys andLeu)and D, (control group, the mixture of Met, Lys and Leu). The results showed that: IGF-ImRNA expression of removal Met group was significantly lower than that of control group(p<0.01) and that of removal Leu group (p<0.05) and removal Lys group was alsosignificantly lower than that of control group (p<0.05).The DNA content of skeletal musclesof removal Met group was significantly lower than that of control group (p<0.01) and that ofremoval Leu group (p<0.05) and the DNA content of skeletal muscles of removal Lys wassignificantly lower than than that of control group (p<0.05); DNA content of jejunum mucousmembrane of removal Met group and Lys group was significantly lower than that of controlgroup (p<0.05). RNA content of skeletal muscles of removal Met group and Lys group wassignificantly lower than that of control group (p<0.05); RNA content of jejunum mucousmembrane of removal Met group was significantly lower than that of control group (p<0.01)and RNA content of jejunum mucous membrane of removal Lys group was significantlylower than that of control group (p<0.05). Serum IGA content of removal Met group and Lysgroup was significantly lower than that of control group (0.05); serum IGM content ofremoval Met group was significantly lower than that of control group (0.01) and that ofremoval Leu group(p<0.05). Serum IGF-I content of removal Met group was significantlylower than that of control group (p<0.01);Serum IGF-I content of removal Lys group and Leugroup was significantly lower than that of control group (p<0.05). Serum Insulin content ofremoval Met group and Lys group was significantly lower than that of controlgroup(p<0.05).Serum GH content of removal Met group and Lys group was significantlylower than that of control group(p<0.05). PUN of removal Met group was significantly lowerthan that of control group (p<0.05). There were no differences about serum TP among fourgroups (P>0.05). It could be suggested that limiting amino acids affect the growth of goatfrom different levels,such as molecule level(such as gene expression of hepatocyte IGF-I),tissue level(such as proliferation of jejunum mucous membrane cell and skeletal muscles cell),immunology level(such as the secretion of IgA, IgM), hormone level (such as GH and Insulin)and protein level (such as PUN). Every level and aspect of promoting growth o f aminolimiting acids is influeced and promoted each other. The role of promoting growth of limitingamino acids is fulfilled by such way.