Effect of Vitamin A and Ambient Temperature on Reproductive Performance of White Leghorn Pullets1

446

D. D. MEYER AND M. WOODBTJRN Poultry Sci. 37: 1224. Martell, A. E., and S. Chaberek, 1959. Organic Sequestering Agents. John Wiley and Sons, N. Y. Martin, W. G., N. H. Tattrie and W. H. Cook, 1963. Lipid extraction and distribution studies of egg yolk lipoproteins. Can. J. Biochem. Physiol. 41: 657-666. McNally, E. H., 1959. Observations on the dispersion and precipitation of egg yolk. Poultry Sci. 38: 1227-1228. Pearce, J. A., and C. G. Lavers, 1949. Liquid and frozen eggs. Can. J. Res. 27: 231. Powrie, W. D., H. Little and A. Lopez, 1963. Gelation of egg yolk. J. Food Sci. 28: 38-46. Smith, A. U., 1954. Effects of low temperatures on living cells and tissues. In Harris, R. J. C , Biological Applications of Freezing and Drying, pp. 1-62. Academic Press Inc., N. Y. Smith, A. U., 1962. Biological Effects of Freezing and Supercooling,- p. 480. Williams & Wilkins, Baltimore.

Effect of Vitamin A and Ambient Temperature on Reproductive Performance of White Leghorn Pullets1 B. L. REID, B. W. HEYWANG, 2 A. A. KURNICK, 3 M. G. VAVICH AND B. J. HULETT Departments of Poultry Science and Ag. Biochemistry, University of Arizona, Tucson, Arizona and United States Department of Agriculture (Received for publication August 17, 1964)

W

ARD and Schaible (1963) reported that numerous dietary ingredients failed to affect the incidence of blood spots in chicken eggs, but vitamin A was not included. Bearse el al. (1960) associated a high incidence of blood spotting of egg yolks with vitamin A deficiency in hens. Hill el al. (1961) reported that the minimum vitamin A requirement of lay-

1 Arizona Agricultural Experiment Station Journal Article #903. 2 Southwest Poultry Experiment Station, ARS, Glendale, Arizona. 3 Present Address: The Ray Ewing Company, Div. of Hoffman-LaRoche Inc., Pasadena, Cal.

ing hens for maintenance of body weight and maximum egg production and the minimum incidence of blood spots was 1,200-1,600 U.S.P. units of vitamin A per pound of diet. Heywang (1952) noted that feed consumption of laying and breeding hens decreased during hot weather but the actual vitamin A requirement of the hen did not increase during prolonged periods of high ambient temperature. He also reported that 2,480 U.S.P. units of vitamin A per pound of diet was not adequate for maximum egg production and maintenance of life during hot weather and con-

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in a home-type freezer. II. Sponge cakes. Food Res. 17: 93-99. Kaloyereas, S. A., A. F. Novak and A. B. Watts, 1962. Heat sterilization of liquid eggs after stabilization treatment with various proteinases. Poultry Sci. 16: 284-288. Lea, C. H., and J. C. Hawke, 1952. Lipovitellin. 2. Influence of water on stability of lipovitellin and the effects of freezing and drying. Biochem. J. 52:105-114. Lopez, A., C. A. Fellers and W. D. Powrie, 1954. Some factors affecting gelation of frozen egg yolk. J. Milk Food Technol. 17: 334-339. Lopez, A., C. A. Fellers and W. D. Powrie, 1955. Enzymic inhibition of gelation in frozen egg yolk. J. Milk Food Technol. 18: 77-80. Lovelock, J. E., 1957. The denaturation of lipidprotein complexes as a cause of damage by freezing. Proc. Royal Society (London), 147: 427^33. Marion, W. W., and W. J. Stadelman, 1958. An investigation of the gelation of thawed egg yolk.

447

VITAMIN A AND REPRODUCTION

EXPERIMENTAL PROCEDURE

Two experiments with Single Comb White Leghorn pullets, hatched during different seasons of the year and fed different levels of dietary vitamin A during the 20 week growing period, were conducted at each of two locations (U.S.D.A. Southwest Experiment Station, Glendale, Arizona and the University of Arizona, Tucson, Arizona). Pullets fed diets containing 250-3,000 U.S.P. units of stabilized vitamin A during the first 20 weeks of life were continued on the same or a higher level of dietary vitamin A during the laying period. Hens were housed in floor pens with straw litter and each diet was fed to duplicate pens of 45 birds in each of the four experiments. Three White Leghorn males were placed in each pen. Egg production and feed consumption were recorded and summarized at 4-week intervals throughout the 44 weeks of each experiment. The incidence of blood spots was determined on all eggs collected on three consecutive days beginning the second week of each 4-week period. Fertility

TABLE 1.—Laying diet Ingredient

(%)

White corn, ground Soybean meal (44% protein) Dried whey (12% protein) Salt Ground limestone Dicalcium phosphate MnSCu • 5H 2 0 (Tech., 70%) Vitamin and Antibiotic Mix1

66.00 22.00 2.00 0.50 5.00 2.50 0.02 2.00

1 Supplied the following per pound of diet: 700 I.C.U. vitamin D3, 2.0 mg riboflavin, 12.5 mg. niacin, 5.0 mg. i-calcium pantothenate, 6 meg. vitamin B12, 2.5 I.U. d-alpha-tocopheryl acetate, 1.0 mg. menadione sodium bisulfite, 200 mg. choline chloride, 56.75 mg. butylated hydroxytoluene, 2.0 mg. procaine penicillin, 10.0 mg. chlortetracycline, 454 mg. methionine hydroxy analogue and 6.0 gm. soybean meal (as a carrier).

and hatchability were determined on all eggs laid during the first week of most 4week periods. Eggs were held at a temperature of 55°F. and put into the incubator on the eighth day. All eggs were candled on the seventh day of incubation. Stabilized vitamin A (10,000 U.S.P. units per gram) was added to the basal diet (Table 1) to obtain the desired dietary vitamin A levels. Feed was mixed at weekly intervals for each treatment. Feed and water were supplied ad libitum. The results of these studies were subjected to the analysis of variance as outlined by Snedecor (1956). Significant differences between treatment means were determined by the multiple range test of Duncan. (1955). RESULTS AND DISCUSSION

Percent egg production increased as the amount of vitamin A was increased to 1,250 U.S.P. units per pound of diet (Tables 2, 3, 4, 5). A further increase to 3,000 (Tables 2, 3, 5) or 6,000 (Table 5) U.S.P. units of vitamin A did not significantly increase egg production. Average egg production of hens fed a diet containing 750 U.S.P. units of vitamin A per pound was 21.5% greater than hens fed a

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eluded that the observed higher requirement resulted from decreased feed intake. During the last few years, increased egg production per hen and high dietary energy levels have resulted in a corresponding decrease in the amount of feed required to produce a dozen eggs. Kurnick et al. (1964) reported dietary vitamin A requirement for pullets during the first 20 weeks of life under various conditions of ambient temperature and rearing location; measurements of feed conversion and vitamin liver storage of vitamin A were compared also. These studies were designed to determine the vitamin A requirement of commercial egg type hens fed a low-fiber, high-energy diet in a subtropical, semiarid climate.

448

B. L. REID, B. W. HEYWANG, A. A. KURNICK, M. G. VAVICH AND B. J. HULETT TABLE 2.—Effect of dietary vitamin A on egg production and feed conversion of White Leghorn pullets at Tucson Experiment 1

Vitamin A added 1 (U.S.P. units/lb.) during both growing and laying periods 500 750 1,000 1,250 3,000 2 3


prod. 50.4"3 68.4" 72.1"= 77.4 d 74.7°d

Periods 7-9 April-August

feed conv.2 5.62»3 4.34" 4.13" 3.92" 4.09"

% egg prod. 26.6»3 47.1" 58.7= 61.6= 59.1=

feed conv.2 8.09"3 5.02" 4.20" 4.03" 4.34"

Periods 1-9 Dec-August

% egg prod. 42.4*3

61.3" 67.6= 72. Id 69.5=d

feed conv.2 6_44»s 4.57" 4.15" 3.95" 4.17"

Vitamin A added to pullet's diet from 0-56 weeks. Pounds feed per dozen eggs. Means having different superscripts are significantly different at the 0.05 level of probability.

diet containing 500 U.S.P. units of vitamin A per pound. The dietary vitamin A requirement of laying hens was no greater during periods of high ambient temperatures than during low ambient temperatures. In the first experiment (Table 2) hens required 1,250 U.S.P. units of vitamin A for maximum egg production, during the winter months which occurred during the first part of the laying year, whereas, 1,000 U.S.P. units of vitamin A was adequate during the summer or latter half of the laying year. At Tucson, November-hatched pullets (Table 4) laid at a lower rate than June-

hatched pullets (Table 2) when fed the same level of dietary vitamin A. At Glendale, egg production in the first study (Table 3) was higher for hens fed the two lower vitamin A levels (500 and 750 U.S.P units) and approximately the same for higher dietary levels compared with hens in the second study (Table 5). However, 1,250 U.S.P. units of vitamin A per pound of diet resulted in maximum egg production in both studies. A significantly lower egg production was obtained from pullets reared on 250 U.S.P. units of vitamin A per pound of diet from 0-10 weeks of age and 1,000 or

TABLE 3.—Effect of dietary vitamin A on egg production and feed conversion of White Leghorn pullets at Glendale Experiment 2 Vitamin A added1 (U.S.P. units/lb.) during both growing and laying periods 500 750 ,000 ,250 3,000 1 2 3

Periods 1-5 Dec-April

%

egg prod. 54.5»3 68.2" 70.3" 73.9= 70.5"

Periods 6-11 April-October

feed conv.2 27*3 33" 24" 09= 57"

% egg prod. 24.9a3

50.9" '57.4= 62.0 d 63.6d

feed conv.2 7.57»3 4.28" 3.90"= 3.60= 3.70=

Periods 1-11 Dec-October

%

egg prod. 38.3a3 58.8" 63.3"= 67.4= 66.7=

feed conv.2 6.52»3 4.30" 4.05" 3.82= 4.10"

Vitamin A added to pullet's diet from 0-64 weeks. Pounds of feed per dozen eggs. Means having different superscripts are significantly different at the 0.05 level of probability.

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1

Perio d s l - 6 Dec. -April

449

VITAMIN A AND REPRODUCTION TABLE 4.—Effect of dietary vitamin A on egg production and feed conversion of While Leghorn pullets at Tucson Experiment 3 Vitamin A added 1 (U.S.P. units/lb.) during both growing and laying periods

1

% egg prod. 31.1»3 54.9 b 65.4° 69.6 d

500 750 1,000 1,250

Periods 9-14 November-April

%

feed

32.0 s 3 46.2 b 50.8° 59.6 d

%

feed

egg prod.

8.86»3 4.90 b 4.17" 4.00°

Periods 1-14 April-April feed

egg prod.

9.09"3 6.36 b 6.33 b 5.54 b

31.5»3 51.2 b 59.1" 65.3 d

8.96»3 5.64 b 5.09 b 4.66 b

Vitamin A added to pullet's diet from 0-76 weeks. Pounds of feed per dozen eggs. Means having different superscripts are significantly different at the 0.05 level of probability.

1,250 U.S.P. units from 11 weeks of age through the laying period as compared with egg production of pullets fed 1,000 or 1,250 U.S.P. units from one day of age through the laying period (Table 5). Egg production of pullets reared on 1,500 U.S.P. units of vitamin A from 0-20 weeks was not significantly changed by increasing the dietary level to 6,000 U.S.P. units when the pullets were 20 weeks of age (Table 5). These observations emphasize the influence of adequate vitamin A intake during early chick life on future reproductive performance.

Feed required to produce a dozen eggs was correlated closely with egg production throughout the 4 experiments. A statistically significant reduction in feed requirement for egg production was obtained by increasing the vitamin A content from 500 to 1,000 or 1,250 U.S.P. units of vitamin A per pound of diet. The feed conversion values were not improved for hens fed the diet containing more than 1,250 U.S.P. units of vitamin A per pound. Average feed conversion (Tables 2, 3, 4, 5) in the four experiments were 7.3, 4.8, 4.4, 4.1 and 4.1 when the diet contained

TABLE 5.—Effect of dietary vitamin A on egg production and feed conversion of White Leghorn pullets at Glendale Experiment 4 Vitamin A added (U.S.P. units lb.)

Periods 1-6 Nov. -April

%

Periods 7-10 April-August

Periods 1-10 Nov.--August

%

(0-10 weeks)

(11-20 weeks)

(Laying period)

Egg prod.

Feed conv.1

Egg prod.

% Feed 1 conv.

Egg prod.

500 750 250 1,000 250 1,250 1,500 1,500 3,000

500 750 1,000 1,000 1,250 1,250 1,500 1,500 3,000

500 750 1,000 1,000 1,250 1,250 1,500 6,000 3,000

37.1" 2 65.9b° 58.5 b 70.5°* 62.0 b 74.8 d 76.5 d 76.6 d 74.0 d

6.41" 2 4.09° 4.85 b 3.98° 4.91 b 3.81° 4.04° 3.81° 3.89°

•12.7"2 36.7 b 37.3 b 47.7° d 41.7 b ° 50.5 d e 55.5" 55.6" 52.6 de

9.43 a2 5.32b° 5.71 b 4.47 b 4.98° 4.37 d 4.41 d 4.11 d 4.11 d

27.4»2 54.2 b ° 50.0 b 61.4 cd 53.9 b ° 65. l d 68. l d 68.2 d 65.4 d

1 2

Feed conv. 1 7.62»2 4.58° 5.19 b 4.17 d 4.94 b 4.04 d 4.19 d 3.96 d 3.97 d

Pounds feed per dozen eggs. Means having different superscripts are significantly different at the 0.05 level of probability.

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2 3

Periods 1-8 April-November

450

B. L. REID, B. W. HEYWANG, A. A. KURNICK, M. G. VAVICH AND B. J. HULETT

TABLE 6.—Blood spots in eggs from White Leghorn •—"its fed different levels of vitamin A Vitamin A added, (U.S.P. units/lb.) Exp. No.

500

750

1,000

1,250

(%)

(%)

(%)

3,000

(%)

1 2 3 4

39.5 26.9 31.6 54.0

31.2 16.1 28.8 33.7

22.3 12.1 24.6 24.0

18.9 10.8 18.8 16.2

6.8 4.4

Average

38.0

27.5

20.8

16.2

6.2

7.5

TABLE 7.—Effect

of dietary vitamin A on fertility of eggs from White Leghorn pullets Vitamin A added, (U.S.P. units/lb.)

Exp. No.

500

750

Summer Winter

(%)

Winter

1250

3000

Summer Winter

Summer Winter

Summer Winter

80.3 91.3 73.0 92.5

(%)

(%)

(%)

(%)

(%)

67.9 88.8 73.9 88.5

80.1 94.0 78.3 90.7

91.2 95.0 70.1 91.5

87.2 95.8 79.5 94.3

90.9 96.5 79.4 97.3

91.2 95.4 86.3 91.1

95.7 96.9 80.4 94.9

79.3 95.9

84.0 97.1

94.1

95.5

Average 79.8

84.3

85.3

87.0

89.2

91.0

91.0

92.0

89.7

92.1

1 2 3 4

(%)

Summer

1000

(%)

(%)

(%)

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500, 750, 1,000, 1,250 and 3,000 U.S.P. units of vitamin A, respectively. Although feed required per dozen eggs varied between the two hatches according to location, the overall agreement among the four experiments was good since similar treatment caused a similar pattern of response in each of the experiments. A stepwise decrease in number of blood spots was noted when vitamin A was increased from 500 to 3,000 U.S.P. (Table 6) units per pound of diet in each of the experiments. Variation was greater between experiments conducted at different locations and with birds of different hatches than within an experiment at a given level of dietary vitamin A. The lowest incidence of blood spots was observed when 3,000 units of vitamin A was fed. The dietary level of vitamin A required for minimum blood spot incidence was higher than reported by Hill et al. (1961), who concluded that the requirement for vitamin A required to minimize

the incidence of blood spots is approximately the same as that required for maximum egg production. An improvement was obtained in percent fertility of eggs from hens as the dietary vitamin A increased from 500 to 1,000 U.S.P. units per pound of diet (Table 7). No further improvement in fertility was obtained by increasing the vitamin A to 3,000 U.S.P. units per pound of diet. Fertility was higher during the cooler portion of the year except in experiment 3 with November-hatched chicks. This indicates the effect of hen age during hot weather on fertility of eggs. The percent hatchability of fertile eggs is shown in Table 8. A reduction in hatchability was obtained when hens were fed less than 1,250 U.S.P. units of vitamin A per pound of diet. A significant improvement in hatchability was obtained in each of the four experiments when the dietary vitamin A was increased from 500 to 750 U.S.P. units per pound. The average improvement was 27.4%, whereas, only 6.7% improvement was obtained by increasing the vitamin from 750 to 1,250 U.S.P. units per pound of diet. Average hatchability of fertile eggs was 6.1% higher during the winter months than during the hot portion of the experiments. Hill et al. (1961) found a 12 % increase in hatchability in one of two experiments when the dietary vitamin A level was in-

451

VITAMIN A AND REPRODUCTION TABLE 8.—Eject ofdietary vitamin A on hatchability of fertile eggs from White Leghorn pullets Vitamin A added, (U.S.P. units/lb.) Exp. No.

. ,K> x

750

1000

1250

3000

Summer Winter

Summer Winter

Summer Winter

Summer Winter

Summer Winter

(%)

(%)

(%)

(%)

(%)

63.3 68.5 51.2 56.4

69.8 84.8 71.9 84.3

88.3 89.4 76.7 83.0

(%)

43.4 51.1 43.4 52.0

74.9 88.1 78.0 90.8

88.7 89.9 87.3 83.8

77.7 91.0 84.0 91.7

90.8 90.8 88.6 90.0

74.1 92.2

89.1 90.0

88.1

84.3

Average 47.5.

59.8

77.7

84.4

83.0

87.4

86.1

90.1

84.8

87.8

1 2 3 4

(%)

The National Research Council (1960) has estimated the vitamin A requirement to be 2,000 U.S.P. units per pound of diet plus a reasonable margin of safety for laying and breeding hens. Results of the current experiments conducted in subtropical semiarid climatic conditions are in close agreement with this value. SUMMARY

White Leghorn pullets fed 250 to 3,000 U.S.P. units of stabilized vitamin A per

(%)

(%)

pound of diet during the first 20 weeks of life were continued on the same or higher level of dietary vitamin A throughout the laying period. The vitamin A requirement of hens for maximum egg production, lowest feed requirement per dozen eggs, maximum fertility and hatchability was 1,250 U.S.P. units during period of high and low ambient temperature. The lowest incidence of blood spots in eggs was found when 3,000 U.S.P. units of vitamin A per pound of diet was fed. Only small differences in the dietary vitamin A requirement of laying hens were observed between periods of high and low ambient temperatures. The influence of adequate vitamin A intake during early chick life on future reproductive performance is discussed. REFERENCES Bearse, G. E., C. F. McClary and H. C. Saxena, 1960. Blood spot incidence in chicken eggs and vitamin A level of the diet. Poultry Sci. 39: 860865. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Heywang, B. W., 1952. The level of vitamin A in the diet of laying and breeding chickens during hot weather. Poultry Sci. 31: 294-301. Hill, F. W., M. L. Scott, L. C. Norris and G. F. Heuser, 1961. Reinvestigation of the vitamin A requirements of laying and breeding hens and their progeny. Poultry Sci. 40: 1245-1254. Kurnick, A. A., B. W. Heywang, B. J. Hulett, M. G. Vavich and B. L. Reid, 1964. The effect of dietary vitamin A, ambient temperature and rearing location on growth, feed conversion and vita-

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creased from 800 to 1,200 units per pound. The criteria of overall improvement in egg production, feed efficiency, fertility, hatchability and lowered incidence of blood spots indicated that 1,250 to 3,000 U.S.P. units of vitamin A per pound of feed was required by White Leghorn pullets. Since the vitamin A requirement is approximately 1,250 to 3,000 U.S.P. units per pound of diet, to maintain optimum performance of healthy hens, the vitamin A requirement is higher and the dietary level should be increased above 1,250 U.S.P. units during certain periods of stress, such as coccidiosis, extreme heat or any condition that decreases feed consumption or nutrient availability. The additional vitamin A will result in higher liver storage of vitamin A and help maintain a sufficient blood level of the vitamin during periods of decreased feed consumption.

(%)

452

B. L. REID, B. W. HEYWANG, A. A. KURNICK, M. G. VAVICH AND B. J. HULETT

min liver storage of White Leghorn Pullets. Poultry Sci. 43: 1582-1586. National Research Council, 1960. Nutrient requirements for domestic animals. No. 1. Nutrient requirements for poultry. Snedecor, G. W., 1956. Statistical Methods. Fifth

edition. The Iowa State College Press, Ames, Iowa. Ward, J. B., and P. J. Schaible, 1963. The failure of certain dietary ingredients to affect the incidence of blood spots in chicken eggs. Poultry Sci. 42: 663-669.

Thyroid Deprivation and Replacement in Chickens1

(Received for publication August 17, 1964)

T

HERE is evidence that both the that RTX and STX produce very similar thiouracil fed chick (Wentworth and responses and that thiouracil produces a Mellen, 1961) and the radiothyroidecto- somewhat less profound hypothyroidism mized (RTX) chick (Mellen and Went- in the chicken. worth, 1962) produce small amounts of It seemed of value to compare the labelled thyroid hormones following the effects of severe and less severe hypothyinjection of I131. Nevertheless, the studies roidism upon a number of parameters of Mellen and Wentworth (1962) and that have been recorded previously, but Snedecor and King (1964) are in agree- not all in the same experiment, to determent that the hypothyroidism produced mine their relative sensitivity to thyroid by the RTX treatment is severe on the hormone deficiency. At the same time, basis of body weight, oxygen consump- replacement of organic iodides by the tion, testis weight and serum cholesterol. feeding of iodinated casein was superThe reductions in body weight and gonad imposed on RTX in one group. Iodinated weight are comparable in extent to the casein was fed to normal birds in one changes caused by surgical thyroidectomy group. The effects of thiouracil and (STX) by Simmons (1943), Blivaiss another antithyroid drug, Itrumil (sodium (1947), and Morris (1951). Mellen and salt of 5-iodo-2-thiouracil)2 were included. Wentworth (1962) reported one experi- The parameters considered were: body ment in which RT X was compared with weight, weight of liver, thyroid, bursa of thiouracil (0.1% of food) feeding. Al- Fabricius, testis, comb and adrenal, and though the effects were the same on blood glucose, serum cholesterol and liver oxygen consumption, thiouracil did not glycogen. All were measured only at the depress body weight as much as did RTX termination of the treatment period. either at three weeks (84. 3 % vs. 79.1% of MATERIALS AND METHODS control) or at ten weeks (69.4% vs. 57.2% of control). The available data suggest The birds used were Hubbard "Barred Silver Cross" males purchased as day-old

1 Supported by Public Health Service Research grant AM 01266 from the National Institute of Arthritis and Metabolic Diseases.

2 Generously supplied by Ciba Pharmaceutical Co. of Summit, New Jersey.

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JAMES G. SNEDECOR AND WILLIAM J. MELLEN Department of Zoology and Department of Veterinary and Animal Science, University of Massachusetts, Amherst