The Effect of Dietary Restriction and Fish Oil Consumption on Small Intestinal Morphology and Liver Cell Changes in Broilers

Increasing the growth rate of broilers leads to some metabolic diseases such as ascites and sudden death syndrome and one of the proposed solutions to reduce its effects is to reduce the growth rate of birds through feed restriction. On the other hand, fat sources rich in omega-3 fatty acids also have a known effect on improving health. The present experiment was designed to investigate the interaction effects of dietary restriction and the use of fish oil in broilers with the focus on studying the effects on the small intestine and liver tissues.

A total of 675 one-day-old male broiler chickens from Ross 308 strain were used in a 3*3 factorial experiment with a completely randomized design with 9 treatments, 5 replications and 15 chickens. The factors studied were dietary restriction at three levels of zero, 6 or 12 hours of starvation during the first week of the growing period and replacement of all dietary oil with fish oil at zero and the last 12 or 18 days of the finisher period.

12-hour dietary restriction during the first week of the growth period reduced feed intake and daily weight gain, and feed conversion ratio decreased due to fish oil consumption. Dietary restriction decreased hepatocyte diameter and hepatocyte nucleus volume and increased hepatocyte cytoplasm volume and hepatic sinusoid volume. Consumption of fish oil significantly reduced hepatocyte diameter, cytoplasm volume and hepatocyte sinusoid volume as well as dose-dependent increase in hepatocyte nucleus volume. In the duodenum and jejunum, dietary restriction reduced villi height. The ratio of crypt depth to villi height also increased in the duodenum due to 12 hours of feed restriction. Consumption of fish oil for 18 days at the end of the finisher period significantly increased the villi length in the duodenum, but in the jejunum, the opposite effect was observed.

The results of this study showed that 6 hours of dietary restriction during the first week of the grower period did not have a negative effect on the production traits of broilers and on the other hand significant tissue changes observed in liver and small intestine tissue testify to the effectiveness of dietary restriction programs and consumption of fish oil on the metabolism of broilers.