Pancreatic insular function in steers as related to the factors of lipid feeding

Insulin is a key factor in control of animal growth. The substrates, produced in the cource of metabolic exchange, or nutrients penetrating through the gastrointestinal tract after digestion affect the insulin synthesis and secretion. In cattle, the insulin stimulation depends on an animal diet but not on the glucose concentration. That is why the ruminants are a suitable model for investigation of the mechanisms of insulin synthesis and secretion. On the steers of Kholmogor breed with the living mass of 240-250 kg we studed the influence of lipid additives to the blood concentration of insulin, glucose, urea and free fatty acids. The lipids of sunflow and flax oils, and the feed additive Bergafat T-300 (Russia) were shown not to change the insulin concentration in blood plasm. Bergafat T-300, recommended for lactating cows, consists of fractionated palm oil free of unsaturated fatty acids, and contains mainly the saturated fatty acids, in particular, the palmitic acid. In contrary, conjugated linolic acid, an ingredient of the Luta-CLA commercial additive preparation («BASF», Germany), increased the insulin concentration in blood plasm and, as a result, the growth of animals fed with Luta-CLA. In this additive the linolic acids is protected from microbial degradation in the paunch of ruminants. After involving into the animal metabolism, it could depress the lipogenesis, presumably through regulation of blood insulin content. So, free fatty acids are unable to be a phisioligical inductor for insulin secretion in ruminants after feeding.