Effect of omega-3 fatty acids and thyme essence on carcass traits of Mahabadi kids
This study was carried out to determine the effects of supplementing long-chain fatty acids of fish oil and thyme on carcass traits in Mahabadi goat kids. For this aim, twenty-eight Mahabadi goat kids (average initial BW of 17/8 ± 2/8 kg, 4-5mo) were randomly assigned to four treatments: 1) control (basal diet), 2) 0.2% thyme essence, 3) 2% fish oil and 4) 2% fish oil +0.2% thyme essence.Animals were kept in individual pens with self-mangers for 94 d. Diet was formulated to met the requirements recommended by NRC with forage (alfalfa and corn silage): concentrate ratio of 30:70 in TMR form. Kids were weighed after 10 d of adaptation and at 21 d intervals after feed restriction and slaughtered at the end of the trial by Iranian traditional procedure . The area of the 9th, 10th, 11th, 12th and 13th ribes together with the adjoined section of spinal column was used to estimate the amount of bone-free meat, fat and bone in the carcass. The meat, fat and bone were weighed after separation and the bone-free meat component stored at −20 °C for the chemical analysis. Data were analized by GLM procedure of SAS 9.1 and tukey test (P≤ 0.05). Addition of 2% fish oil increased fat depth over 12th rib (P< 0.05). Dressing percentage, eye muscle area, carcass length, liver and kidney weight, abdominal and kidney fat were not affected by treatments(P>0.05). Percentages or weights ribs dissected muscle, fat and bone, and percentages of wholesale cuts of the carcass were not affected by fish oil and thyme essence(P> 0.05). The results of this experiment indicate that supplementation of goat kid diet with fish oil and thyme did not influence carcass traits but, fish oil increased back fat thickness.