The Effect Of Early Castration On The Growing Development And Histological Structure Of Organs In Male Mice

To study the effects of gonadectomy on mammalian body indexes, such as average daily gain, daily growth rate and carcass composition, and the physiological structure of the main functional tissues and organs, such as heart, liver, spleen, lung and kidney. In this study, we chose mouse as model and caponized (hemicastration and castration) or sham-operated at 24d of age, and then slaughtered at 71 d and measured luxuriant data on growth and slaughter indexes among sham, hemicastration and castration male mice to find the significant changes. The body weight of all experimental animals were determined every day; the body length, chest tape, tail length were measured every other week; the heart weight, liver weight, spleen weight, lung weight, kidney weight and plasma testosterone levels were also measured when sacrificed. The results showed that:1. There were no significant differences in average daily gain between hemicastration and sham-operate groups (p>0.05). The average daily gain of castration group was similar to the sham-operate group from 24d to 32d (p>0.05), and the same trend was found from 47d to 57d. Gonadectomy resulted in reduced the average daily gain between hemicastration and sham-operate (p<0.05) from 33d to 46d, as with the trend from 58d to 71 d (p<0.05 or P<0.01).2. Body Weight, body weight without testes, carcass weight, carcass weight without testes, the volume ratio of carcass weight, dressing percentage, dressing percentage without testes, volume, density, total skeletal muscle weight and the volume ratio of skeletal muscle exhibited no significant differences between hemicastration and sham-operate (p>0.05). The body weight, body weight without testes, carcass weight and carcass weight without testes density in sham-operate were higher than those in the castration group (p<0.05 or p <0.01). There were no significant differences in the volume ratio of carcass weight, dressing percentage, dressing percentage without testes, volume, total skeletal muscle weight and the volume ratio of skeletal muscle between castration and sham-operate (p>0.05).3. There were no significant differences in body length, chest tape and tail length between hemicastration and sham-operate groups (p>0.05). The heart weight, cardiac index. Spleen weight, spleen index, lung weight and lung index showed on significant differences between hemicastration and sham-operate groups (p>0.05). but liver weight. liver index, kidney weight and kidney index in the hemicastration were significant fewer than those in the sham-operate (p<0.01). The heart weight, cardiac index, spleen weight, spleen index, lung weight, lung index, liver weight, liver index, kidney weight and kidney index in sham-operate were significant higher than those in the castration (p<0.05 orp<0.01).4. It is obvious that the physiological structures of the heart, liver, kidney and spleen had changed in the castration. Myocardial cells arranged more loosely and the interstice between myocardial cells showed wider in castration group compared to control group. The hepatocyte exhibited smaller cell volume, worse cell integrity, wider vacuolated interstice and spotty necrosis in castration. Spleen, castration group showed more macrophage obviously. We found that glomerulus was swelling, and capsular space was wide in castration.Collectively, the gonadectomy not only resulted in reduced average daily gain, daily growth rate and carcass composition by decreasing in muscle mass, but also decreased visceral weight and changed the physiological structures of viscera.