Effects of nutritional-induction of chronic inflammation on broiler gut health and performance

We have previously observed that feeding a diet with 30% of rice bran to broilers induced a low-grade chronic intestinal inflammation. Moreover, ingredient quality also can interfere in the animal’s gut health. Therefore, the current experiment focused on further evaluating the broiler response to diets with high rice bran and with/or rancid oil inclusion. For that 1,344 Cobb male by-product day-of-hatch chickens were raised to 22 d of age and randomly assigned to 6 treatments. The treatments were (1) negative control (NC, corn and soybean diet); (2) NC diet + bacitracin; (3) diet with rancid oil (7.2 mEqO₂); (4) diet formulated with 20% rice bran + rancid oil; (5) diet with 20% rice bran inclusion and (6) diet with 30% rice bran. At 15 and 22 d, necropsies were conducted to evaluate gastrointestinal (GI) gross lesions, histological examination of the jejunum through microscopic I See Inside (ISI), and performance (feed intake, weight gain and feed conversion) were calculated. No differences in GI tract gross lesions between treatments were observed at either 15 or 22 d. The rancid oil did not affect performance or produce histologic alterations in the jejunum. However, broiler performance was negatively affected by both rice bran diet inclusions at both days (P < 0.01) with the worse performance throughout the experiment observed in the animals fed with the 30% rice bran diet. Moreover, at 15 d, the broilers in the rice bran groups presented an increase in lamina propria thickness (P = 0.002), goblet cells (P = 0.003), and inflammatory infiltration (P= 0.0005), and an increase in total ISI score. At 22 d, the jejunum of birds fed with rice diets presented an increase in goblet cells (P < 0.001) and congestion (P = 0.040) compared with NC. The inclusion of 30% rice bran, also increased epithelial thickness (P= 0.021) and proliferation of enterocytes (P = 0.004) compared with the bacitracin-fed animals. In conclusion, high inclusion of rice bran in the broiler feed reduced intestinal health and induced chronic intestinal inflammation, which had a detrimental effect on performance.

Key Words: intestinal inflammation, rice bran, intestine.

Presented at the 9th Symposium on Gut Health in Production of Food Animals, St. Louis, USA, 2021. For information on the next edition, click here.