Spinal deformity frequently produced by pinealectomy and the role of melatonin on developing the spine in chicks

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The developing the spine is one of the most important process in all vertebrates. In our previous study the rate of deformity of the spine in pinealectomized layers was about 70% even though 2 months after pinealectomy. In the present study we examined the rate of spinal deformity in broilers by pinealectomy. The rate of spinal deformity in pinealectomized broilers at 8 day- and 15 day-old was 70 and 100% respectively, in which severe deformity at 15 day-old was 63%. Administration of melatonin in pinealectomized broilers significantly decreased the ratio and degree of spinal deformity. These results show the rate of the deformity of the spine in broilers was much higher than that of layers. Therefore, in the next step, the influence of body growth on the degree of spinal deformity was investigated. Pinealectomized broilers at 2 day-old were kept under dietary foods for 8 days ; full diet, 80% diet or 60% diet, respectively. The ratio of spinal deformity was not significant deferent among three dietary groups. These results show that the induction of spinal deformity in pinealectomized chicks is independent on the body growth. In the next study we examined whether the removal of the pineal gland changes bone minerals and plasma Ca concentrations. Calcium and phosphorus levels in the vertebra at 7 days after pinealectomy were significantly lower than those of controls, and on the other hand the plasma Ca concentrations significantly increased. Administration of 3-fold Ca on dietary food decreased the ratio and degree of spinal deformity. These results suggest that the pineal gland affects the bone metabolism in the process of developing chick spine.