การศึกษาผลการเสริมกลีเซอรีนดิบและรูปแบบการให้อาหารต่อสมรรถนะการผลิตและลักษณะซากในไก่กระทง

Abstract

The objectives of this study were to determine (1) the digestibility and metabolizable energy of crude glycerin, and (2) effect of crude glycerin supplementation and feeding regime on productive performance and carcass characteristics in broiler In Experiment 1, the digestibility and metabolizable energy of crude glycerin were observed. Eight male Hisex Brown birds at 27 weeks old with 2.79 kg of initial weight, were used in this study. Birds were divided into two groups with four birds each. Each bird was arranged in each metabolic cage. From the results, the digestibility percentage for crude glycerin was 108.25. The apparent metabolizable energy of crude glycerin was 5,423.54 kcal/kg for AME and 5,421.99 kcal/kg for AME, while the true metabolizable energy (TME, TME) was 5,452.42 and 5,452.42 kcal/kg, respectively. In Experiment 2, the effects of crude glycerin on productive performance, feeding regime, carcass characteristics and its feeding cost were observed in broiler chickens. Three hundred sixty one day old females Cobb500 with 44.34 g of initial weight were allotted to receive three treatment diets according to a completely randomized experimental design (CRD). Group one, birds received standard diet for 42 days. Group two, birds received diet with 5% crude glycerin straight 1-42 days. Group three, birds received standard diet at 1-21 days of age and then received diet with 5% crude glycerin at 22-42 days of age. Each treatment was separated into four replicate of 30 birds each. Birds were reared in evaporative cooling house for 42 days. They were offered feed and water ad libitum during the entire experimental period. On the 3rd and 6th week of age, eight birds per treatment were sampled and slaughter for the determination of carcass characteristics. Data were analysed by using analysis of variance, whereas the differentiations of means were determined according to Duncan's new multiple range test (DMRT). At 1 to 21 days old, no significant difference was found in final weight, weight gain, feed intake ADG and FCRin all groups (P>0.05). At 22-42 days old, the birds fed diet at 5% crude glycerin at 22-42 days of age had significantly better weight gain and FCR than those received diet with 5% crude glycerin at 1-42 days of age (P<0.05). No significant difference was found on productive performance at 1-42 days of age (P>0.05). In terms of carcass characteristics, broilers at twenty-one days old, all groups had no significant difference in retail parts (fillet, drumstick, wing, thigh) and carcass composition (meat, skin, bone, whole fat) (P>0.05). At 42 days old, effect of glycerin supplemented in diets and feeding regime had no significant difference from birds in the control group. Considering some physical characteristics of the breast muscle (m. Pectoralis major), neither age of broiler in either control or supplemented diet groups at 21 and 42 days of age showed no significant difference in pH, pH, CIE color system (L", a and b ́), shear force, drip loss and cooking loss percentage (P>0.05). In terms of feed cost of broiler production, this study indicated that the lowest feed cost per gain was found in birds received diet with 5% glycerin at 22-42 days of age (29.30 Baht per kg). Nevertheless, the highest feed cost per gain was found in birds received diet with 5% glycerin from 1-42 days of age (25.37 Baht per kg) In conclusion, crude glycerin could be supplemented in broiler diet but it was recommended to feed at 22-42 days of age (second stage). This was due to the better productive performance and lowest feed cost per gain than those received diet with crude glycerin for 42 days were obtained.