# The Effect of Dietary Oil Level and Multi‐Enzyme Supplementation on Performance, Bone Mechanical Properties and Mineral Contents, Intestine Morphology and Immune Response in Broiler Chickens

## TL;DR

This study shows that adding soybean oil and multi-enzymes to broiler chicken diets improves growth, bone strength, and gut health.

## Contribution

The study explores the combined effects of soybean oil levels and multi-enzyme supplementation in low-energy diets for broiler chickens.

## Key findings

- Higher soybean oil levels improved weight gain and feed efficiency during the grower and finisher periods.
- Multi-enzyme supplementation enhanced bone strength and reduced gizzard and intestine weight.
- Vegetable oil reduced liver weight, suggesting inhibition of fat production.

## Abstract

Supplementing broiler diets with non‐starch polysaccharide multi‐enzymes (NMEs) has been shown to improve nutrient utilization and performance. However, the interaction between dietary soybean oil levels and NME supplementation in diets requires further exploration.

The aim of the present study was to evaluate the dietary soya bean oil level and NME supplementation in a low‐energy wheat‐based diet's effects on performance, bone mechanical properties and mineral contents, blood metabolites, small intestine morphology and immunity criteria in the broiler chickens.

A total of 360 one‐day‐old mixed‐sex Ross 308 broiler chicks were randomly assigned to 6 treatments, 5 replicates/treatment and 12 (6 females and 6 males) birds/replicate. Experimental treatments were included in a factorial arrangement of 0%, 6% and 12% levels of diet metabolizable energy supplied by soy oil (MESO) with/without NME supplementation. For starter (1–10 days), grower (11–24 days) and finisher (25–38 days) rearing periods, six isocaloric and isonitrogenous experimental diets were formulated and fed ad libitum.

There was no significant difference in growth performance traits between birds fed diets with different levels of MESO during the starter period. As well as increased dietary MESO levels, weight gain and feed conversion ratio during grower, finisher and whole rearing periods linearly improved. Moreover, abdominal fat relative weight, breast meat cooking lost and jejunum muscular thickness linearly increased, and liver relative weight and jejunum crypt depth linearly decreased. Dietary NME supplementation led to improved production performance during the starter, grower and whole experimental periods; enhanced tibia bone strength and abdominal fat; decreased gizzard and intestine relative weight; and decreased jejunum muscular thickness.

It was concluded that dietary NME supplementation and supply of 12% of broiler chickens metabolizable energy requirements through soy oil have a positive effect on the growth performance, bone strength, liver and small intestine health of broiler chickens fed low‐energy wheat‐based diet.

Dietary supplementation by vegetable oil (VO) plays an important role in lipid metabolism and its body deposition. Lower liver relative weight of broiler chickens fed a diet supplying 12% of ME requirement through VO suggests that VO could cause an inhibition of lipogenesis.