a. zare shahneh

The accumulation of excess triacylglycerol and fatty acids in nonadipocytes results in lipotoxicity, cellular dysfunction, and cell death. Although feed restriction is an effective and practical management technique to prevent the obesity in broiler breeders, after the peak of egg production hens have propensity to be overweight. Lipotoxicity in hepatocytes and follicular cells of laying hens could cause liver disfunction, ovarian abnormalities, and therefore, decline egg production.

This study was conducted to determine the effect of Pioglitazone on egg production and plasma metabolites in broiler breeder hens.

 Thus, forty birds were randomly allotted to four groups with 10 birds in each and were fed standard diet supplemented with different levels of Pioglitazone at 0, 10, 20 and 40 mg/bird per day from 45 through to 51 weeks of age.

The results indicated that 20 and 40 mg levels improved egg production and quality (P<0.05). In regard to plasma lipids, Pioglitazone at levels of 20 and 40 mg had hypolipemic effects and could effectively decrease plasma glucose, triacylglycerol, low density lipoprotein and cholesterol (P<0.05). In addition, the activity of liver enzymes, as a criterion of liver health, was improved in hens receiving 20 and 40 mg Pioglitazone (P<0.05). Also, necropsy observations showed that liver and abdominal fat weights significantly decreased by dietary supplementation of 20 and 40 mg Pioglitazone (P<0.05).

In conclusion, the current study indicated that Pioglitazone at levels 20 and 40 mg/bird/day could improve performance of post-peak female broiler breeders through lowering plasma lipids.

In order to determine the effects of fetal growth rate on plasma concentrations of glucose, triglyceride, total protein, and urea in ewes, this experiment was conducted at Animal Research Station of Tehran University Agricultural College. Sixteen pregnant Varamini ewes were allocated to 4 groups (n=4). During the breeding season, ewes of group 1 were mated by Varamini ram, animals in groups 2, 3 and 4 were mated by Moghani, Afshari and Shall rams, respectively. Because of the different genetic capacities of sires, fetal growth rate was expected to be different in various groups. Ewes in all groups were fed the same ration, so it was expected that differences in fetal growth rates would affect the mobilization of maternal fat and protein storage and blood levels of their metabolites. Blood samples were collected from jugular veins of ewes during the last 8 weeks of pregnancy and first week after lambing. Plasma levels of glucose, cholestrol, and triglycerid were not different among 4 groups. Total plasma protein in ewes carrying heavier fetuses was lower than in ewes with lighter fetuses (p<0.05). Conversely, plasma urea concentrations in ewes with heavier fetuses were higher than in ewes with lighter fetuses.

Effects of the β-adrenergic agonist metaproterenol were studied daily gain, carcass composition and feed consumption of Varamini female lambs were studied. Thirty lambs were randomly assigned to a randomized complete block design with three groups (treatments) and two blocks (live weight). The ration was similar for all groups (ME: 2.6 MCal/kg, CP: 14.9%) and lambs were fed ad libitum. Metaproterenol was injected subcutaneously at 0 (control), 7 (low dose) and 14 (high dose) µg kg-1 w75. Lambs were weighed at 20-day intervals. Mean daily weight gain and feed conversion ratio improved significantly by metaproterenol (P<0.05), but feed intake was not affected. Hot carcass weight, carcass weight minus fat-tail, dressing percentage and longissimus muscle characteristics were different among the three groups (P<0.01). Physically separated fat from several depots and fat-tail weight significantly reduced in the metaproterenol groups. Carcass fat content decreased but carcass protein content increased in metaproterenol treated lambs.