Calcium is the main component of bones and eggshells. Its main function is to promote bone growth, form eggshells, regulate the normal activities of nerves and muscles, and maintain the acid-base balance in the body. If the calcium level in the diet is unreasonable (too high or too low), it has a significant adverse effect on the health and performance of the breeder and its offspring. The nutritional standard for broiler breeders requires that the calcium content in the feed be 2.8%-3.3%, while in actual production, the calcium content in the feed is often higher than this range. The hazards of long-term consumption of high-calcium feed for broiler breeders are briefly described below.
1 damage to the kidneys
1.1 visceral gout
Poultry gout is a nutritional metabolic disease characterized by a large amount of urate accumulation due to the disorder of protein metabolism in poultry, which is characterized by deposition on the surface of internal organs and other interstitial tissues. There are many causes of visceral gout. One of the reasons is the improper proportion of calcium and phosphorus in the feed and the high calcium content (super standard 50%). The pathological changes were: white pericardium deposits on the surface of the pericardium, liver, spleen, mesentery and peritoneum; the kidneys were swollen and stained, the kidney surface and the renal tubules were filled with white urate; the ureter Expansion, obviously thicker.
1.2 kidney, ureteral stones
The cause of kidney and ureteral stones is the same as that of visceral gout. Sometimes, kidney and ureteral stones appear at the same time as gout. The pathological changes were: 3-4 times of kidney enlargement, yellow-white betel nut-like appearance on the surface; a large amount of white urate precipitated on the kidney section; unilateral or bilateral ureters were significantly thicker, and the ureter and renal tubules were filled with urate crystallization.
2 effects on the performance of broiler breeders
Regarding the effect of dietary calcium levels on the performance of broiler breeders, Dr. John T. Brake conducted experimental studies at different stages of broiler breeder production, and the results showed that high calcium feed was consumed throughout the laying period, and broiler breeders were The egg production rate is reduced and the mortality rate is increased. Three groups were set up to feed 2755%, 3.0%, and 3.3% of the egg-producing diets. Results: The peaks of egg production in the three experimental groups were 76.1%, 75.6%, and 72.2%, respectively; The 2.75% calcium diet group had the highest egg production rate. High calcium diets can reduce the energy level of feed and reduce feed intake.
3 The impact on the hatching rate of breeding eggs
In the production practice, the author experienced 3 cases of broiler breeder eating high calcium feed and causing a decrease in hatching rate. The fertilization rate of the eggs was above 92%, while the hatching rate of hatching eggs was 30%-60%, lower than normal. 20%-50%, the content of calcium in the tested breeder diet was 3.8%-4.8%, which was 0.5%-1.5% higher than the normal range.
The reason why the high calcium feed causes the hatching rate of the broiler breeder eggs is reduced: because the broiler breeder eats the high calcium feed for a long time, the quality of the eggshell is changed, resulting in an increase in eggshell density and relative thickening of the eggshell, thereby reducing the eggshell. The permeability prevents the internal and external exchange of gas and water, and the egg does not reach the normal water loss rate (12%-13%). Decreased water loss rate will reduce the egg chamber, which will cause the oxygen content in the air chamber to decrease, causing the chicks to lack oxygen when breaking the mouth and breaking the shell, which makes the hatching rate of the eggs decrease.
4 impact on other aspects of the
4.1 calcium feed triggers phosphorus deficiency
Excess calcium and phosphorus combine to form calcium phosphate excreted, reducing the absorption rate of phosphorus. Phosphorus reduction, increase urinary calcium levels, stress on the kidneys, high calcium and low phosphorus diets easily cause kidney and ureteral calculi.
4.2 calcium feed affects the absorption of manganese.
Excessive levels of calcium and phosphorus in the feed will reduce the utilization of manganese. High calcium and high phosphorus form calcium phosphate precipitate in the intestine, and the precipitated adsorbed manganese is excreted in the body, thereby causing the body to be deficient in manganese. When egg laying broiler lacks manganese, it often shows reduced egg production, low hatching rate of eggs, and poor embryo development after hatching.
4.3 high calcium feed can cause breeder diarrhea
In the period when the broiler breeder just started to change the egg-producing diet, if the calcium content is high, it is easy to cause diarrhea, because the addition of stone powder in the feed stimulates the intestinal tract to accelerate the intestinal peristalsis. - "Modern Animal Husbandry and Veterinary"
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