Fat metabolism in laying hens on the background of different lipid components in the diet

The mechanisms of the effects of different oils with different fatty acid profiles on poultry performance remain poorly understood. Therefore, the aim of this study was to investigate the duodenal activity of digestive enzymes and the digestibility of nutrients in the diets of laying hens fed different oils in the same diet (sunflower, soybean, rapeseed and linseed oils, 2.6% of the total diet). The test was conducted on 10 laying hens of the Hysex white cross with chronic duodenal (7 birds) or ileal (3 birds) fistulas. Different oils influenced lipase and alkaline phosphatase activity in duodenal chyme. The highest lipase and alkaline phosphatase activity was found when soybean oil was administered. At the same time, there was a significant (P<0.05) decrease in lipase activity by 35.6-37.6% only when all other oils were administered. Crude fat digestibility was at the highest level when using rapeseed oil. Introduction of this oil into the diet also resulted in the highest digestibility of crude fiber and crude protein and significantly higher availability of amino acids: lysine, threonine, serine, glycine, alanine, histidine and cystine (P<0.05 compared to the control period with the introduction of sunflower oil). In summary, a positive correlation was found between duodenal protease activity and crude protein digestibility with rapeseed oil (r=0.52) and sunflower oil (r=0.54). It was concluded that unrefined sunflower and rapeseed oils are the most physiologically effective oils in diets for laying hens.