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-In the present study we measured serum glucose, leptin, total cholesterol and total protein concentrations in repeat breeder cows and compared them with fertile cows. For this aim, 20 repeat breeder cows and 20 fertile cows were used as material. Repeat breeder cows were found to have lower levels of leptin and glucose as compared with fertile ones. No significant differences in total cholesterol and total protein levels were observed between the two groups. No significant correlation of leptin with glucose, total cholesterol and total protein was observed in fertile and repeat breeder cows. Low concentrations of glucose and leptin can have some effects on reproductive problems as repeat breeder and help to understand potential mechanisms impairing fertility in repeat breeder cows.

Amylin is a member of the calcitonin family of hormones cosecreted with insulin from the pancreatic beta-cells that can act as an osteoblast mitogen and as an inhibitor of bone resorption in mice and humans. The aim of this study was to investigate the role of amylin on bone formation and some egg parameters in hens. The study was performed in 60 hens aged 10 wk. Thirty hens constituting the treatment group were s.c. injected with amylin at a 75 microg/kg dose every other day. The remaining hens were used as the control group. Five birds from the treatment and control groups were slaughtered at 14, 16, 18, and 20 wk of age and serum and bone parameters were compared between the treatment and control groups. The remaining 20 hens were fed without any amylin injection until 35 wk. All hens at the end of the 35th week were slaughtered and then serum, bone, and egg parameters were assessed. In the treatment group, bone calcium levels increased, whereas serum calcium levels decreased. This dose of amylin also increased the cortical width of tibiotarsuses in hens. Eggshell thickness was found thicker in the treatment group than in the control group. Overall, the results of this study suggest that amylin may stimulate the bone and eggshell quality by increasing calcium uptake from the bloodstream and may influence the sustainability of yield in hens.

The objective of this study was to assess the correlations of amylin (a pancreatic polypeptide hormone) with some hormonal, biochemical and bone parameters in pullets. Forty 18-week-old pullets were used. Plasma amylin, CT (calcitonin), 1,25 (OH)2 vitamin D (1,25 dihydroxycholecalciferol ), serum osteocalcin, glucose, ALP (alkaline phosphatase), cholesterol, and triglycerides, as well as weight, length and total volume of tibiotarsi were measured. Plasma amylin concentration was negatively correlated with serum cholesterol (p<0.05) and triglycerides (p<0.05) concentrations. Plasma amylin concentration was significantly and positively correlated with plasma calcitonin concentrations (p<0.001). Serum ALP and plasma amylin concentrations were positively correlated (p<0.01). There were no correlations between amylin hormone and other parameters. Based on these results, it is possible to conclude that endogen amylin may effect cholesterol, triglycerides, calcitonin, and ALP levels in pullets without changing some other hormonal, biochemical and bone parameters related to calcium and lipid metabolism.