The Effects of Different Oil Sources on Performance, Digestive Enzymes, Carcass Traits, Biochemical, Immunological, Antioxidant, and Morphometric Responses of Broiler Chicks

This research evaluate the influence of different oil sources, namely fish oil (FO), coconut oil (CocO), canola oil (CanO), or a mixture of the three oils (MTO)—included at 1.5% in broiler diets—compared to a no oil-supplemented diet. Hence, 250 unsexed, 1-day-old Cobb chicks were weighed and randomly allocated into five dietary treatment groups of 50 chicks each and five replicates per group. Oil-supplemented diets significantly increased the growth, improved the feed conversion ratio (FCR), and decreased the abdominal fat percentage compared to the control diet. Amylase was significantly elevated due to feeding the FO- or CocO-supplemented-diet compared to the control diet, whereas lipase increased due to offering CocO- and CanO-enriched diet; chymotrypsin increased due to different oil sources. High-density lipoprotein cholesterol (HDL-C) increased markedly due to offering an oil-supplemented diet, but low-density lipoprotein cholesterol (LDL-C), the LDL-C:HDL-C ratio, and malondialdehyde (MDA) decreased. Blood plasma immunoglobulin (Ig) G and IgM significantly increased due to feeding CocO, CanO, or MTO compared to the control group, whereas FO increased IgG only. FO- and CanO-containing diets resulted in the highest increase in α2-globulin and γ-globulin. The antibody titer to avian influenza (HIAI) and Newcastle disease (HIND) were significantly elevated due to CocO supplementation compared to the control group. The bursa follicle length and width and thymus cortex depth were increased considerably due to the FO-supplemented diet compared to the control, but the follicle length:width ratio decreased. The villus height:depth ratio was significantly elevated due to both the CanO and MTO diets. The antioxidant status improved considerably due to the addition of CocO and CanO. Both CanO and MTO similarly increased plasma T3, T4, and the T3:T4 ratio. In conclusion, oil supplementations at 1.5% enhanced growth performance and immune status, improved the blood lipid profile and antioxidants status, and the effect of the oil sources depends on the criteria of response.

Introduction

Poultry is a very important industry. Indeed, it is estimated that in 2020, chicken will be the most consumed animal protein in the world. Fat and oil are generally used in poultry diets to increase the energy concentration. Fat-enhanced feeds increase the efficiency of the feed energy and productivity in poultry (1, 2). Moreover, oil improves the absorption of fat-soluble vitamins, the palatability of diets, decreases the dustiness of feeds, and reduces the passage rate of feed in the gut, which provides more time for the sufficient absorption of nutrients (3–5). Besides, the fatty acid profile of muscle tissue mirrors the dietary lipid profile and can alter the blood levels of lipoproteins and triglycerides (6–8). As a rule, the utilization of unsaturated fatty acids (UFAs) in poultry diets improves the product quality (for example, ω3 and ω6). This improvement is concordant with the consumers' interest (9, 10) and immune response (3, 4, 11–13).

Fish oil (FO) has high percentages of long-chain polyunsaturated fatty acids (PUFA), particularly ω3 fatty acids that increase oxidative damage and negatively affect the flavor of animal products. FO is low in ω6 fatty acids and linoleic acid (14, Order Now