Simple Summary
Cereal grains such as maize, barley and wheat are the main energy source in chicken feeds. However, barley and wheat are harder for young birds to digest and often need extra oil to match the energy of maize. Emulsifiers are feed additives that help birds make better use of dietary fat. In this study we fed broiler chickens diets based on maize, barley or wheat, each with or without an emulsifier, and measured how well the birds grew, their meat yield, bone strength, gut structure and digestive enzymes. Birds fed the wheat-based diet consumed significantly less feed and had a lower body weight, while the barley and wheat diets reduced carcass yield. In the emulsifier treatments, dietary energy was reduced by lowering the amount of added soybean oil. Compared with the standard-energy diets, these emulsifier-supplemented reduced-energy diets supported similar growth, restored carcass yield and increased tibia ash content in the barley and wheat diets, and increased the activity of the fat-digesting enzyme lipase. These results suggest that emulsifier supplementation of reduced-energy diets is a useful feeding strategy, particularly when maize is replaced by barley or wheat, as it may reduce feed costs without impairing growth.
Abstract
The purpose of this study was to evaluate the effect of emulsifier addition to reduced-energy maize-, barley- or wheat-based diets on selected indicators in broilers. In this experiment, a total of 540 unsexed (mixed-sex) one-day-old Ross 308 chicks were allocated to six treatment groups using a 3 ×x 2 factorial design (five replicate pens of 18 birds). Each diet was fed either as a standard-energy diet without emulsifier or as a reduced-energy diet (−50 kcal/kg ME, achieved by lowering soybean oil inclusion) supplemented with 500 g/ton emulsifier. The wheat-based diet reduced body weight and feed consumption but improved feed conversion ratio compared with the barley-based diet. Feeding a maize-based diet increased carcass yield and the breast (meat, skin and bone) ratio but decreased the leg (two thighs and two drumsticks, with meat, skin and bone) ratio compared to feeding a wheat-based diet. The addition of emulsifiers to barley- and wheat-based diets increased carcass yield. The negative effects of barley- and wheat-based diets on the carcass compared to the maize diet were compensated for by the addition of emulsifiers to the diet. The highest values for tibia breaking strength and tibia ash content were obtained with wheat-, maize-, and barley-based diets, respectively. Tibia ash increased with the addition of emulsifiers to barley- and wheat-based diets. Barley- and wheat-based diets resulted in higher pancreatic amylase activity compared to maize-based diets. Pancreatic lipase activity increased with the addition of emulsifiers. The wheat-based diet increased villus surface area compared to other cereals. The addition of emulsifier to the diet increased villus height/crypt depth but decreased other villus measurements. In conclusion, it can be said that adding emulsifiers to reduced-energy broiler diets feed is more effective in increasing carcass yield in barley- and wheat-based feeds, and that emulsifier addition compensates for the energy deficit in the diet.