This investigation was undertaken to evaluate the effects of dietary ZnSO4 supplementation on ammonia volatilization and nitrogen retention in hen manure. One hundred twenty, 45-wk-old commercial Leghorn laying hens were sequentially fed diets with 1000, 2000, and 3000 ppm Zn as ZnSO4 (Zn-1000, Zn-2000, and Zn-3000), then followed by two control dietary periods with 114 ppm Zn (Control-1 and Control-2) for a total of five consecutive eight-day experiment periods, respectively. When hens were fed the 1000 and 2000 ppm Zn treatment diets, room ammonia levels were significantly reduced compared to the control diets. Dietary Zn treatments reduced the decomposition of uric acid, resulting in an increase in manure total-N retention compared to the control fed birds. The 1000 ppm Zn supplement had no adverse effects on hen body weight, feed consumption, egg production, egg weight, albumen height, or shell thickness. However, hens fed the diet containing 3000 ppm Zn had significantly depressed body weight, feed consumption, egg production, egg weight, and shell thickness. Zinc levels of egg contents increased linearly as dietary Zn levels increased. These levels in eggs would not be a problem for human consumption because these are much less than the daily Zn recommended dietary allowance. Although land application of such manure will not cause environmental problems or crop toxicity, proper monitoring of soil and crop Zn levels and effective nutrient management planning would be well advised.
Notes
1Vitamin and mineral premix = corn chop, 47.5%; wheat middlings, 26%; limestone, 15.5%; salt, 5%; vitamin mix, 2%; choline, 2%; trace mineral mix, 2%. Vitamin mix = vitamin A, 120.2 KIU; vitamin E, 106 IU; riboflavin, 80.52 mg; pantothenic acid, 103.62 mg; niacin, 317.45 mg; choline, 5817.23 mg; folic acid, 5.17 mg; thiamine, 17.36 mg; pyridoxine, 22.48 mg; biotin, 653.25 μ g; vitamin B12, 100 μ g; vitamin D3, 60 KIU. Trace mineral mix = calcium, 5.55%; phosphorus, 0.37%; potassium, 0.43%; magnesium, 0.31; manganese, 2414 ppm; iron, 2086 ppm; copper, 202 ppm; cobalt, 0.076 ppm; zinc, 2230 ppm; sulfur, 0.095%; sodium, 1.94%; chloride, 3.29%; iodine, 48 ppm; selenium, 12 ppm.
2Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2MD = missing data.
3 n = 47 per mean. The room ammonia data, which were taken every 15 min from 6:00 PM to 5:45 AM during each eight-day experiment period, were used for statistical analysis.
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2 n = 3 per mean. The mixed manure from two cages was a replicate.
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2 n = 120 per mean. The body weight was based on individual bird weight on day 8 of each experiment period.
3 n = 30 per mean. Feed consumption (g/day/bird) = feed consumption per cage per day/ 4 (four birds per cage).
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2 n = 3 per mean. The mixed manure from two cages was a replicate.
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2 n = 3 per mean. The mixed manure from two cages on day 8 was a replicate.
3 n = 3 per mean. The mixed egg content from five eggs on day 7 was a replicate.
1Zn-1000 = Control diet + 1000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the first eight-day period; ZnSO4-2000 = Control diet + 2000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the second eight-day period; ZnSO4-3000 = Control diet + 3000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4 during the third eight-day period; Control-1 = hens fed control commercial layer diet during the fourth eight-day period; Control-2 = hens fed control commercial layer diet during the fifth eight-day period.
2 n = 30 per mean. Daily egg production from a cage containing four birds was a replicate.
3 n = 30 per mean. Each egg was a replicate.