Abstract
In this study eight feeding trials were carried out at the Poultry Farm of Bangladesh Agricultural University (BAU), Mymensingh and Vobkhali village at Sadar Upzilla of Mymensingh district in Bangladesh to investigate the growth potentials and meat yields of indigenous (desi) chicks up to the target weight of around 1kg in confinement and scavenging with supplementation in rural areas by feeding diets containing different levels of energy and protein. The first experiment was conducted with 360 indigenous (desi) chicks to achieve a target weight of 750g in confinement. The objective was to find out appropriate cost-effective diets to explore higher growth performance under confinement. Four dietary treatments with three replications each of 30 chicks were considered for comparison. Diets consisted of three isocaloric (ME 2800 kcal/kg DM) diets: conventional diet (broken rice 65%+ rice polish 31%), low protein density (LPD), moderate protein density (MPD) and high protein density (HPD) diet contain 19%, 21% and 23% CP respectively. The birds were fed ad libitum during the study period. The results showed that body weight gain and survivability were increased significantly and FCR improved (P<0.01) with an increase in the level of protein in the diets. Considering the feed cost and profit margin, HPD diet was more cost-effective. In the second trial, 228 chicks of 3 weeks age were reared up to a target body weight of 850g. The birds were divided into four dietary treatments with three replications each of 19 birds. Diets were: conventional diet (similar to experiment 1); low nutrient density (LND): ME 2400 kcal/kg + CP 19%; moderate nutrient density (MND): ME 2600 kcal/kg + CP 21% and high nutrient density (HND): ME 2800 kcal/kg + CP 23%. In both experiments, the contents of CP, ME, calcium (Ca) and total phosphorous in HPD and HND diets were satisfied in accordance with the requirements of broiler suggested by Bureau of Indian Standard (BIS, 1992). Birds receiving HND diet achieved the target body weight 850g with significantly higher from birds that received other diets (P<0.05). The birds of HND group showed lowest feed conversion efficiency (4.26). Feeding HND diet had a tendency of higher breast meat and drumstick meat yields than other groups at 12 weeks of age. Feeding higher levels of energy and protein in indigenous (desi) chick's diet significantly increased profitability. In the 3rd trial, 140 female chickens of 12 weeks old were divided into 4 dietary treatments for this study and reared on littered floor in an open sided house up to the point of lay. Four diets that contained: conventional diet (CD): broken rice 65% and rice polish 31%, low protein density (LPD): CP 15%, moderate protein density (MPD): CP 17% and high protein density (HPD): CP 19%. Metabolizable energy was 2700 kcal/kg in each diet. Final body weight was significantly improved in birds receiving MPD diets than the other diets (P<0.05) during growing period of 12-22 weeks. There is no profit in any dietary groups during 12 to 22 weeks of age. In the 4th trial, 72 female chickens of 12 weeks old were divided into 4 dietary treatments and reared on littered floor in an open sided house. Diets contained: CD, broken rice 65% and rice polish 31%, low nutrient density (LND): ME 2500kcal/kg + CP 15%, moderate nutrient density (MND): ME 2700 kcal/kg + CP 17% and high nutrient density (HND): ME 2900 kcal/kg + CP 19%. Experiment continued from 12 weeks of age to the point of lay. Body weight was significantly improved in MND and HND diets (P<0.05) than the birds of CD and LND diet during this period. During the pre-laying period, body weight was significantly (P<0.05) improved in MND and HND diets in comparison with CD and LND diet. There was no profit in all dietary groups in the experimental period. Fifth experiment was conducted with 216 three weeks old desi chicks up to target weight of 950g in the Poultry Farm of BAU, Mymensingh. Four iso-nitrogenous (CP 23%) starter diets differing in energy contents were formulated for conducting the feeding trial. Diets were very low energy density (VLED), low energy density (LED), moderate energy density (MED) and high energy density (HED) contained ME 2400, 2600, 2800 and 3000 kcal/kg respectively for starter period. Four growing diets were VLED, LED, MED and HED contained ME 2300, 2500, 2700 and 2900 kcal/kg respectively and all diets contained 17% CP. Body weight and Body weight gain was significantly improved in HED and MED diets (P<0.001) than the birds of VLED and LED diet during 3-14 weeks. FCR improved significantly (P<0.05) in VLED, LED group than MED and HED dietary group. Energy levels of diet had no effect on survivability. Breast meat, drumstick and head weight were significantly (P<0.05) higher in HED, MED, LED than VLED groups. Return per bird increased significantly (P<0.05) with increasing level of the dietary energy densities in diets. In experiment 6, a total of 32 village households were considered for the study. Each farmer was provided six chicks. Live weight and body weight gain increased significantly (P<0.001) with increasing levels of supplementation (0%, 25%, 50%, 75%) at 14 weeks of age. Dressing percentage was significantly higher in 25%, 50% and 75% feed supplementation groups respectively than 0% supplementation group at 14 weeks of age (P<0.05). Breast weight was significantly higher in 50% and 75% feed supplementation groups than 0% and 25% supplementation groups (P<0.01). Net return was significantly higher in 25%, 50% and 75% feed supplementation groups respectively than no supplementation group (P<0.05). In experiment 7, four week's old chicks were divided into 2 dietary treatments and reared on littered floor in an open sided village house. Diets were moderate energy density (MED): ME 2800 kcal/kg + CP 23% and high energy density (HED): ME 3000 kcal/kg + CP 23%. Feed and water were provided ad libitum throughout the experimental period. The results of weight gain showed significant (P<0.01) increase in HED than MED group. FCR and survivability had no statistical difference between the groups. In experiment 8, day old chicks were divided into 2 dietary treatments and reared on littered floor in an open sided house. Diets contained, moderate energy density (MED): ME 2800 kcal/kg + CP 23% and high energy density (HED): ME 3000 kcal/kg + CP 23%. There were no differences in final body weight, body weight gain, feed intake, FCR, net return and survivability between the birds that received MED and HED diets. Considering the feed cost and profit margin, it was concluded that supplementation of 75% MED diet appeared to be most cost-effective and therefore could be considered for feeding indigenous chicks to approximately 1kg target weight by exploring scavengeable feed resources in the village. The results of this study also indicate that a nutrient density of 2800 ME kcal/kg and 23% CP diet would be enough to optimize feed intake, growth rate and better meat yield of indigenous (desi) chicks up to 14 weeks of age in confinement. Such nutrient density in desi chick's diet increases profitability.