Regulation of eating behavior on lysine and threonine imbalance diets in chicks

The authors investigated the eating behavior, growth and content of limitative amino acids in tissues and organs of broiler-chicken of the SK-Rus' 2 cross. Imbalance was made by supplementation of low-protein wheat diet with a crystal amino acid mixture without lysine and threonine, respectively. It was shown that imbalance induced an acute anorectic reaction and the reduction of the growth intensity, concentration of free lysine and threonine in blood plasma, free lysine in hy-pothalamus and also pronounced increase of amino acids content in liver. The same time it was no differences in lysine and threorune content in tissues of liver and brain. Peritoneal injection of brain extracts from threonine imbalanced chicks to the same chicks enhanced the anorectic reaction; neuropeptide Y injection to the same chicks improved the feed consumption. The trail with alternative sources of deficient amino acids demonstrated the animals have a mechanism of identification of the alternative lysine and threonine sources.