Dietary Sodium for Laying Hens

Dietary Sodium for Laying Hens

373 RESEARCH N O T E S Katz, M. A., L. R. Dugan, Jr. and L. E. Dawson, 1966. Fatty acids in neutral lipids and phospholipids from chicken tissues. J...

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373

RESEARCH N O T E S

Katz, M. A., L. R. Dugan, Jr. and L. E. Dawson, 1966. Fatty acids in neutral lipids and phospholipids from chicken tissues. J. Food Sci. 31: 717-720. Marion, W. W., S. T. Maxon and R. M. Wangen, 1971. Lipid and fatty acid composition of turkey liver, skin and depot tissue. J. Am. Oil Chem. Soc. 48: 391-392. Mickelberry, W. C , J. C. Rogler and W. J. Stadelman,

1964. Effect of dietary fats on broiler tissues. J. Am. Dietetic Assoc. 45: 234-239. Mountney, G. J., 1966. Poultry Products Technology. The Avi Publishing Co., Inc., Westport, Conn. Quackenbush, F. W., 1973. Personal communication. Risek, R. L., B. Friend and L. Page, 1974. Fat in today's food supply—level of use and sources. J. Am. Oil Chem. Soc. 51: 244-250.

DIETARY SODIUM FOR LAYING HENS REID

(Received for publication August 3, 1976)

ABSTRACT Dietary sodium requirements of laying hens in open type and evaporatively cooled housing were determined to be 0.126 and 0.145% of the diet, respectively. The lowest level of 0.04% sodium supported average rates of production of 49.1 and 60.3% in the two houses for the 28 weeks of the study. POULTRY SCIENCE 56: 373-374, 1977

INTRODUCTION

T

WO recent reports have dealt with the effects of sodium deprivation on egg production rate. Whitehead and Shannon (1974) suggested that low sodium diets could be used for controlling egg production. A diet containing only 0.038% sodium caused egg production to cease and to return when adequate dietary sodium was fed. In a second paper, (Hughes and Whitehead, 1974) sodium deprivation did not influence feather picking or general activity of laying birds. The N.R.C. suggests a level of 0.15% sodium as being adequate for laying hens; however, no information is available on the effects of housing on such requirements. The purpose of the present study was to evaluate the dietary sodium requirements of the laying hen under conventional and evaporatively cooled housing conditions. EXPERIMENTAL PROCEDURE The White Leghorn pullets used in this

Arizona Agricultural Experiment Station Journal Article No. 2644.

study were housed in colony cages (5 birds /cage) and 4 cages in each house were employed on each dietary sodium level. Dietary sodium levels ranged from the unsupplemented basal diet which contained 0.04% to a high of 0.37%. The basal diet used in this study consisted of 64.5%ground milo, 17.25% soybean meal, 4.5% dehydrated alfalfa meal, 1.75% animal fat, 7.75% ground limestone, 1.75% dicalcium phosphate, 0.1% trace mineral mix, 2.0% vitamin mix (in soybean meal) and 0.1% DL-methionine. The composition of the trace mineral and vitamin mixes used in this study are the same as previously reported (Reid and Weber, 1976). Birds were fed the respective experimental diets for seven 28day periods. The sodium contents of the diets were determined at each mixing by atomic absorption spectrophotometry. The water supplied to the birds contained 75 p.p.m. sodium, although water intakes were not monitered. RESULTS AND DISCUSSION Increasing the dietary sodium content from 0.04 to 0.1% with the addition of sodium

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B. L.

Department of Animal Sciences, University of Arizona, Tucson, Arizona 85721

RESEARCH NOTES

374 TABLE 1.—-Effect

Dietary sodium content, % (analyzed) 0.04 0.10 0.15 0.19 0.21 0.22 0.37

of dietary sodium on laying hen performance

Conventional Feed conversion % kg./dz. production 2.52 49.1 2.13 71.8 1.92 76.8 1.96 66.1 1.88 70.9 1.87 69.7 1.83 73.5 2.00x 69.7x

Both houses Feed conversion % kg./dz. production 2.41 54.7 2.00 71.4 1.94 75.9 1.94 70.8 1.91 72.8 1.89 73.0 1.86 74.6

day under conventional housing conditions and 149 mg. per day for the evaporatively cooled birds. Those birds in the conventional house required 210 mg. sodium per egg produced while those in the evaporatively cooled conditions consumed 201 mg. per egg produced at the requirement level. Under the conditions of this study, we were unable to confirm the results of Whitehead and Shannon (1974) concerning the cessation of egg production at a dietary sodium level of 0.04%. These results suggest that in order to force molt birds through the use of sodium restriction, special care must be taken to produce dietary sodium levels below the amounts employed in this study. It should be noted that the water supplied to these birds contained 75 p.p.m. sodium. REFERENCES Hughes, B. O., and C. C. Whitehead, 1974. Sodium deprivation, feather pecking and activity in laying hens. Br. Poultry Sci. 15: 435-439. Reid, B. L., and C. W. Weber, 1976. Calcium availability and trace mineral composition of feed grade calcium supplements. Poultry Sci. 55: 600-605. Whitehead, C. C , and D. W. F. Shannon, 1974. The control of egg production using a low-sodium diet. Br. Poultry Sci. 15: 429-434.

AUGUST 14-18, 1977. JOINT ANNUAL MEETINGS OF THE AGRICULTURAL INSTITUTE OF CANADA, AND THE CANADIAN INSTITUTE OF FOOD SCIENCE AND TECHNOLOGY, UNIVERSITY OF GUELPH, GUELPH, ONTARIO, CANADA

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chloride produced a significant increase in egg production under each of the housing conditions (Table 1). Birds fed the lowest level of dietary sodium (0.04%) did not cease egg production at any time during the experiment and layed at a rate of 49.1% in the conventional house and 60.3% under the evaporatively cooled conditions. The feed conversion data essentially parallel those obtained for egg production and were significantly improved with the addition of dietary sodium. Birds in the conventional housing conditions layed at a rate of 69.7% throughout the study with a feed conversion of 2 kg. of feed/dz. eggs -while those fed under evaporatively cooled conditions layed at a rate of 74% with a feed conversion of 1.92. These data were subjected to regression analyses in order to arrive at the estimates of the sodium requirement under each of the housing conditions. Birds fed in a conventional open house required an estimated 0.126% sodium for optimum egg production while those in the evaporatively cooled house required 0.145% sodium. Combining the data for both houses produced an estimate of the sodium requirement as 0.126% of the diet. Extrapolation of these requirements to intake values yielded figures of 141 mg. sodium per

Evaporatively cooled Feed conversion % kg./dz. production 2.31 60.3 1.98 71.0 1.96 75.0 1.85 75.6 1.88 74.6 1.87 76.3 1.87 75.6 1.92y 74.0y