Effect of hemp seed cake instead of cottonseed meal on ghrelin and growth hormone in lambs

The aim of this study was to determine plasma ghrelin and growth hormone levels in lambs fed cottonseed meal and hemp seed cake and to determine the relationships between these levels and fattening performance. The animal material of the study consisted of 20 Akkaraman single male lambs weaned at an average age of 3 months. The lambs were randomly distributed to the control and treatment groups with 10 lambs in each group. The control group lambs were fed with a ration containing cottonseed meal (PTK) as protein source and the treatment group lambs were fed with a ration containing hemp seed cake (KTK). Before the start of the seventy-day fattening trial, the lambs were subjected to an acclimatisation programme for two weeks and during this period ad-libitum fattening feed and 200-250 g of alfalfa hay per animal were given. Live weights of lambs were determined at the beginning of the acclimation period and on days 0, 30 and 60 of feeding. In order to determine serum ghrelin and growth hormone concentrations, blood samples were taken from the vena jugularis of the lambs before feeding on the same control days and hormone levels were determined by ELISA method. The live weights at the beginning of the acclimatisation period, at the beginning of fattening (day 0), on the 30th and 60th days were found to be 25.76 kg and 25.92 kg, 26.69 kg and 26.67 kg, 35.13 kg and 35.24 kg, 42.22 kg and 41.63 kg in control (PTK) and treatment (CTK) groups, respectively. Serum ghrelin hormone concentrations measured at the beginning of the acclimatisation period, at the beginning of fattening (day 0), on days 30 and 60 were 66.26 ng/ml and 94.07 ng/ml, 56.66 ng/ml and 77.19 ng/ml, 71.52 ng/ml and 93.28 ng/ml (p<0.01), 67.96 ng/ml and 54.59 ng/ml in control and treatment group lambs, respectively. Serum growth hormone concentrations measured at the beginning of the acclimatisation period, at the beginning of fattening (day 0), on days 30 and 60 were 1.92 ng/ml and 3.06 ng/ml (p<0.05), 1.96 ng/ml and 3.33 ng/ml (p<0.05), 2.86 ng/ml and 3.98 ng/ml, 5.19 ng/ml and 5.50 ng/ml in control and treatment group lambs, respectively. Low correlations were determined between ghrelin and growth hormone levels and body weights.