December 23, 2008

Studies by the Roslin Institute in Scotland have found that exposure to ultra violet light could decrease the possibility of vitamin D deficiency in poultry, a common reason broiler chicks are culled.

The study concentrated on Tibial Dyschondroplasia (TD), a syndrome in which distorted bone growth leads to impaired gait and consequently welfare.

The research team set up an experiment with 60 one-day old Ross broiler chicks, which were split between a control environment and a shed featuring UV lamps.

The team hung the 26 watts reptile lamps 1.4 metres above floor level. The chicks were exposed to UV light for 12 hours after placement, with lighting in both the control and test sheds maintained at the same overall luminance.

Both groups were fed a slightly unbalanced diet, low in calcium and phosphorus, to increase the chances of TD appearing. Vitamin D levels in the blood were measured daily, and the chicks were killed at 14 days old to analyse their bone structure.

The results were encouraging. Two percent of the treated broiler chicks displayed symptoms of TD, with 98 percent having normal bone growth plates. That compares to just 43 percent of normal growth in the control group, with 39 percent having rickets - possibly an early indicator of TD - and 18 percent showing TD wounds.

The treated birds were 6 percent heavier than the control group, and displayed significantly stronger, more resilient and healthier leg bones than the control flock. Blood vitamin D levels were also significantly higher throughout the test.