Effects Of Different Levels Of Dietary Calcium On Fatty Liver Syndrome In Young Laying Hens

Fatty liver syndrome (FLS) of laying hens was caused by excessive content of fat in the diet. It was a kind of abnormality of metabolism function in the chicken body. It is a kind of nutritional and metabolic disease, characterized by fatty degeneration and bleeding of liver, and even acute death. The onset of FLS had close relationship with calcium and energy of the feeds.In the study, classic fatty liver model was induced by feeding with high-energy ration. The effects of different levels of calcium and crude fat in chicken liver, production trait and biochemical indicator of blood of the model chicken were researched.10819-week-old Hy-line brown laying hens was randomly divided into6groups, according to two energy levels (12.68and13.37MJ’kg"1) and three calcium levels (2.62%,3.7%and4.4%). The six groups were normal energy with normal calcium, high energy with normal calcium, normal energy with high calcium, high energy with high calcium, normal energy with low calcium and high energy with low calcium respectively. Each group composed of6repetitions and each repetition include of3chickens. There were36hencoops (40cm x35cm x35cm). Trough was parted from each hencoop. There was no limitation on water-drinking and16h illumination everyday. Every chicken was fed110g feeds. The weight of each egg and chicken, feed consumption, laying rate, egg shell strength and thickness, abdominal fat and liver index were measured and contrastive analysis was made. The blood and liver sample were collected. Crude fat of the liver and biochemical indicator of the blood serum were evaluated, and paraffin section were made.Research on biochemical indicator of the blood serum made the discovery that energy level of the feeds had no significantly relationship with blood Ca(P>0.05), whereas the calcium level had exceedingly significant effect(P<0.01). Along with the heighten of calcium level in feeds, the blood Ca increased, and lower calcium level would exceedingly significant decreased blood Ca(P<0.01). Both the energy level and the calcium level had no significant effect on ALP and GLU in the blood serum(P>0.05). TG concentration in the blood serum of the low calcium group was significant higher than that of the normal and high calcium group(P<0.05).From the study of crude fat concentration of the liver, the energy level of the feeds significantly affect the fat concentration of the liver(P<0.05) as well as the crude fat in the liver cells(P<0.05). High energy feeds could promote fat heaping in liver, but high energy level with high calcium level group was significantly lower(P<0.05). Low calcium group had no such effect(P>0.05). So presumption was made that high blood Ca might inhibit the fat heaping, and lower the body weight and fat concentration. High calcium level feeds had certain inhibition on fatty liver.In the normal group, the liver were purple red, with sharp edge and flexibility and well-stacked texture. Whereas in the high energy low calcium and high energy normal calcium group, the liver were earth yellow, swelling, with blunt border, embrittled texture, felt greasy, and had bleeding point on its surface. The liver tissue sections showed that normal energy group and high calcium group have no hepatic steatosis. But high energy low calcium group and high energy normal calcium group showed significant steatosis. Because high energy and high calcium group has no significant hepatic steatosis, we could say that calcium plays an important role in the inhibition of fatty liver disease process.In this experiment, the high-energy diet successfully induced FLS of laying hens. Experimental results showed that high energy diet caused FLS and low egg production rate at the same time. The diet calcium was in closely related to FLS. Low calcium diet resulted in the accumulation of fat in the physical and reducing fat consumption. So it can increase the incidence of fatty liver. The most important is the increasing of calcium in diet has a positive effect on the inhibition of fatty liver.