Sodium Requirements for the First Seven Days in Broiler Chicks

2003 Poultry Science Association, Inc. Sodium Requirements for the First Seven Days in Broiler Chicks S. L. Vieira, 1 A. M. Penz, Jr., S. Pophal, and J. Godoy de Almeida Departamento de Zootecnia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 7712, Porto Alegre, RS 91540-000, Brazil Primary Audience: Nutritionists, Poultry Producers, Veterinarians SUMMARY A study was carried out to investigate the sodium requirements of broiler chicks in the first week post-hatching using diets with two dietary electrolyte balances (DEB). During the first week, birds were given feeds with four levels of total sodium (0.12, 0.24, 0.36, and 0.48%) and two DEB (Na + + K + Cl = 160 or 240 meq/kg). Feeds given thereafter to 42 d had common formulation. Both sodium and DEB affected live performance of chicks. Increasing sodium in the feed led to improvements in BW and feed conversion through the first week. Birds fed increased sodium had up to 25% increased water consumption and had corresponding reductions of 12 and 13% in carcass and excreta DM in the seventh day of age. Water consumed remained 6% higher in birds fed increased sodium through the second week of age. Regression analysis were run for BW gain and feed conversion, which estimated sodium requirements between 0.38 and 0.40% in the first week post-hatching. Since responses to increased sodium did not remain with broilers marketed at 6 wk of age, the use of this study s estimated requirements will depend on the need to improve the performance immediately after hatching. There was an increased mortality at 4 d of age when the levels of sodium were maximized (0.48%). Increasing DEB from 160 to 240 meq/kg demonstrated benefits on weight gain and feed conversion, but only limited to the first 4 d of age. Key words: acid-base balance, broiler chick, chloride, electrolyte, potassium, sodium 2003 J. Appl. Poult. Res. 12:362 370 DESCRIPTION OF PROBLEM Sodium is an essential nutrient known to influence several aspects of normal animal growth. Sodium deficiency leads to reduced growth and feed consumption and impairs feed conversion [1, 2]. Sodium also affects water intake [3], acid-base balance [4], and basal metabolism [5]. Despite its well-known essentiality, several studies have demonstrated a wide range of variation for the sodium requirements of chickens. This is especially the case with chicks to 21 d of age [6, 7, 8, 9, 10, 11]. NRC [12, 13] has increased its recommendations for sodium during this period, from 0.15 to 0.20%, in its last two editions. However, some changes in feeding programs have been occurring with commercial integrators adopting pre-starter feeds to be fed from placement until 7 to 10 d of age. These have ingredient differences and higher concentrations of several nutrients when compared with standard starter diets to 21 d. Evaluations of sodium requirements in the first week posthatching are lacking in the literature. Sodium chloride, the most common source of sodium, costs little and provides chloride, 1 To whom correspondence should be addressed: slvieira@ufrgs.br.

VIEIRA ET AL.: SODIUM REQUIREMENTS IN BROILER CHICKS 363 another essential element. Both nutrients, along with potassium, are the electrolytes required in greater amounts for birds. They are also closely related with the acid-base balance because cations are alkalogenic and anions acidogenic [14]. Therefore, cation-to-anion balance in feeds should influence investigations on the requirements for these minerals, and interactions between them have to be taken into account when formulating feeds for poultry. Mongin and Sauveur [15] proposed that the simplest way of expressing cation-to-anion interrelationships in feeds is to use the proportion of Na +,K +, and Cl in meq/kg of feed, which they called dietary electrolyte balance (DEB). Mongin [14] conducted several studies, clearly demonstrating that overall bird performance is improved when DEB is increased to a level of 250 meq/kg. However, other studies have shown optimization of bird performance in a wider electrolyte balance range [11, 16]. Excess water consumption contributes to increases in litter moisture and leg problems in poultry and could be affected by the sodium concentration in the feed. Therefore, nutritionists in general are very cautious on the use of high levels of sodium in feeds. This argument, however, may be of low relevance for a prestarter feed used during the first week, considering the small amount of excreta produced in this period. A considerable amount of time usually passes from the time the chick hatches until its placement in the broiler house, so dehydration is a common problem in commercial operations. An estimation of sodium requirements in this period should consider that higher levels of electrolytes, especially sodium, than those usually accepted as requirements from 1 to 21 d of age would benefit the chick by inducing greater water intake. This study was designed to investigate the effects of altering sodium allowances in the first week post-hatching in feeds having diverse DEB on the live performance of broiler chicks, but also on the responses related to water intake, carcass, and excreta moisture. MATERIALS AND METHODS One-day-old male broiler chicks, Ross Ross 308, obtained from a commercial hatchery, were placed in experimental units consisting of 1-m 2 steel batteries located in a temperaturecontrolled room automatically regulated to maintain bird comfort. Experimental treatments consisted of feeds formulated with corn and soybean meal to meet or exceed NRC [13] recommendations, provided from placement to 7 d of age with four sodium concentrations (0.12, 0.24, 0.36, and 0.48%) and two DEB (Na + + K + Cl = 160 or 240 meq/kg). Prior to preparing the experimental feeds, each ingredient was analyzed for total Na +,K +, and Cl and their analyzed values used for feed formulation. Sodium chloride, calcium chloride, and potassium carbonate added to the feeds were based on manufacturer analyses and, therefore, their guaranteed concentrations were used (39.34% Na + and 60.66% Cl in sodium chloride; 63.89% Cl in calcium chloride; and 56.58% K + in potassium carbonate). Kaolim, an inert ground rock without nutritional value, was used to complete the diets. Analysis of the drinking water indicated that Na +,K +, and Cl concentrations were 14.0, 4.5, and 19.0 mg/l, respectively. Feeds were prepared in batches of 50 kg. First, 490 kg of a basal corn-soybean meal feed was mixed. Then, amounts of limestone, sodium chloride, calcium chloride, potassium carbonate, and kaolim were included to produce each individual treatment, as shown in Table 1. Feeds were not pelleted. Fifteen birds were placed in each experimental unit and supplied with water and feed ad libitum in a completely randomized design of eight treatments of five replicates each in a factorial arrangement with four Na + levels and two DEB. Therefore, 40 units having 600 birds at the beginning were used. Light was continuous throughout the experiment. Birds in each replicate were group-weighed at placement and then at 4, 7, 14, 21, and 42 d of age. Mortality was recorded throughout the experiment and expressed as percentage in each period. Statistical analyses of percentages were performed after transformation to arcsine of their squared root, but the values presented in tables are the actual means. Body weights and feed consumption were recorded weekly, and the calculated feed conversions were corrected for the weight of dead birds on a daily basis.

364 JAPR: Research Report TABLE 1. Composition of experimental feeds (%) Sodium (%) DEB = 160 meq/kg DEB = 240 meq/kg Ingredient 0.12 0.24 0.36 0.48 0.12 0.24 0.36 0.48 Corn 50.0 Soybean meal 39.2 Meat and bone meal 4.0 Soybean oil 2.35 Vitamin and mineral premix A 0.5 Dicalcium phosphate 1.29 DL-Methionine 0.33 L-Lysine 0.16 L-Threonine 0.12 Choline chloride 0.05 Limestone 0.026 0.030 0.034 0.038 0.346 0.364 0.382 0.400 Sodium chloride 0.231 0.536 0.841 1.147 0.231 0.536 0.841 1.147 Calcium chloride 0.818 0.814 0.810 0.806 0.402 0.379 0.356 0.334 Potassium carbonate 0.163 0.145 0.127 0.110 Kaolim 0.925 0.620 0.3150 0.009 0.858 0.576 0.294 0.009 Calculated composition, % ME, kcal/kg 2,900 Crude protein 24.0 Calcium 1.00 Nonphytate phosphorus 0.50 Digestible lysine 1.30 Digestible methionine 0.64 Digestible methionine + cystine 0.94 Digestible threonine 0.87 Choline, mg/kg 1,800 Chlorine 0.654 0.837 1.020 1.202 0.454 0.628 0.802 0.975 Potassium 1.140 1.138 1.135 1.133 1.232 1.220 1.208 1.195 A Supplied per kilogram of feed: vitamin A, 5,000 IU; vitamin D3, 500 ICU; vitamin E, 15 IU; vitamin K 3, 2 mg; vitamin B 12, 15 mcg; biotin, 0.15 mg; folic acid, 1 mg; niacin, 50 mg; pantothenic acid, 25 mg; pyridoxine, 5 mg; riboflavin, 5 mg; thiamin, 3 mg; copper, 8 mg; iodine, 0.5 mg; iron, 100 mg; manganese, 80 mg; selenium, 0.15 mg; and zinc, 70 mg. Water consumption was recorded daily to 14 d of age by checking the volume of water left in the drinkers at the end of each day and subtracting this from all water allocated to each drinker in the preceding 24-h period. Two chicks from each replication at 4 and 7 d of age were killed by cervical dislocation. They were ground and oven-dried for 24 h at 105 C for determination of body carcass moisture. Total excreta produced in each battery were collected daily. A sample of each daily composite averaging 100 g was dried for moisture determination using the same methodology employed on the carcasses. Data were analyzed using the GLM procedure of SAS [17] and Tukey s studentized procedure was used for mean separation when the main effect F-test was considered significant (P < 0.05). Results are presented in tables as contrasts of the main factors, which are footnoted to provide expanded information when interactions between main factors were significant (P < 0.05). Linear regression analysis was conducted for the increasing levels of sodium with the objective of estimating sodium requirements [18]. RESULTS AND DISCUSSION Most of the variable effects were independent from one another at 7 d of age or in the period from 1 to 7 d; therefore, analysis of regression allowed a more accurate understanding of the impact of Na + on birds performance, and derivation of the quadratic regressions was used to estimate the maximum responses for each Na + level. Sodium frequently receives little attention in the formulation of broiler feeds. The major reason

VIEIRA ET AL.: SODIUM REQUIREMENTS IN BROILER CHICKS 365 TABLE 2. Body weight and average daily weight gain of broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed A BW (g) Weight gain (g) 1d 4 B d 7 d 14 d 21 d 42 d 1 4 d 4 7 d 1 7 d 7 14 d 14 21 d 21 42 d 1 42 d Dietary Na, % P 0.501 0.001 0.001 0.057 0.071 0.818 0.001 0.001 0.001 0.391 0.414 0.597 0.965 0.12 47 89 b 154 b 426 826 2,533 42 c 65 b 107 b 272 400 1,707 2,486 0.24 46 97 a 171 a 451 866 2,518 51 b 74 a 125 a 280 415 1,652 2,472 0.36 46 99 a 170 a 446 852 2,535 53 ab 71 a 124 a 276 406 1,683 2,489 0.48 46 100 a 169 a 443 860 2,526 54 a 69 a 126 a 277 417 1,666 2,480 P 0.478 0.002 0.055 0.167 0.489 0.520 0.001 0.379 0.107 0.448 0.013 0.737 0.426 160 46 94 164 437 855 2,543 48 70 118 273 418 1,688 2,497 240 46 98 168 446 847 2,524 52 70 122 278 401 1,667 2,478 CV, % 2.7 6.4 5.4 4.9 4.4 3.4 12.4 7.1 7.8 6.0 5.1 4.5 3.1 B Na DEB (P < 0.03): 0.12 160 = 87; 0.12 240 = 90; 0.24 160 = 95; 0.24 240 = 100; 0.36 160 = 101; 0.36 240 = 99; 0.48 160 = 95; 0.48 240 = 103. TABLE 3. Feed consumption and feed conversion of broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed A Feed consumption (g) Feed conversion (g/g) 1 4 d 4 7 d 1 7 d 7 14 d 14 21 d 21 42 d 1 42 d 1 4 d 4 7 d 1 7 d 7 14 d 14 21 d 21 42 d 1 42 d P 0.238 0.001 0.005 0.007 0.587 0.864 0.756 0.001 0.040 0.001 0.636 0.747 0.676 0.708 0.12 56 86 b 142 b 362 b 602 3,427 4,533 1.34 c 1.32 1.33 b 1.33 1.51 2.01 1.82 0.24 57 93 a 150 a 387 a 622 3,426 4,585 1.14 b 1.26 1.20 a 1.38 1.50 2.07 1.85 0.36 57 93 a 150 a 382 a 604 3,426 4,562 1.08 ab 1.29 1.19 a 1.38 1.49 2.04 1.83 0.48 54 93 a 147 a 385 a 618 3,554 4,704 1.01 a 1.33 1.17 a 1.41 1.48 2.13 1.90 P 0.006 0.512 0.229 0.759 0.007 0.804 0.385 0.067 0.856 0.576 0.211 0.549 0.905 0.570 160 55 92 147 380 629 3,472 4,628 1.16 1.30 1.22 1.39 1.50 2.06 1.85 240 57 91 148 378 594 3,445 4,565 1.12 1.30 1.22 1.36 1.48 2.05 1.84 CV, % 3.7 5.9 3.9 4.9 6.7 10.8 8.0 12.0 4.9 6.2 5.5 8.4 10.4 7.57

366 JAPR: Research Report FIGURE 1. Body weight gains and feed conversions of broiler chicks 1 to 7 d of age and sodium levels in their feeds. for that is the high availability and low cost of sodium chloride. In this study, overall performance of birds given the 0.12% sodium in the feed was clearly impaired (P < 0.05) when compared with those fed the diets having sodium at 0.24% and higher. Improvements obtained in BW gain, feed consumption, and feed conversion with different sodium levels were limited to the period the birds were being fed the experimental diets and disappeared afterwards (Tables 2 and 3). However, regression analysis showed plateaus for BW gain and feed conversion from 1 to 7 d with 0.38 and 0.40% Na +, respectively [19], which are observable in Figure 1. Feed consumption was also dependent on Na + in the feeds, but its maximum response was attained with Na + at 0.34% [19]. Birds receiving diets having DEB of 240 meq/kg showed greater BW gain from 1 to 4 d (P < 0.002). Sodium requirements of chicks seemed dependent on the DEB from hatching to 4 d of age, when there was a significant interaction, but not to 7 d. Increasing the sodium contents to 0.48% caused mortality five times greater than with Na + TABLE 4. Mortality of broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed, % A Days 1 4 4 7 1 7 7 14 14 21 21 42 1 42 P 0.001 0.499 0.001 0.546 NS 0.999 0.102 0.12 0.0 c 0.0 0.0 c 0.7 0.0 2.7 3.4 0.24 1.2 b 0.8 2.0 b 0.0 0.0 2.7 4.7 0.36 0.0 c 0.0 0.0 c 0.7 0.0 2.7 3.4 0.48 5.0 a 0.0 5.0 a 0.0 0.0 2.5 7.5 P 0.001 0.376 0.001 0.157 NS 0.740 0.044 160 2.8 0.3 3.1 0.0 0.0 2.4 5.5 240 0.0 0.0 0.0 0.7 0.0 2.8 3.5 CV, % 314.9 383.1 283.7 406.0 0 127.1 110.8

VIEIRA ET AL.: SODIUM REQUIREMENTS IN BROILER CHICKS 367 TABLE 5. Daily water consumption of broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed (ml/bird) A Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 7 7 14 1 14 P 0.516 0.012 0.001 0.001 0.001 0.001 0.001 0.005 0.003 0.001 0.001 0.001 0.060 0.399 0.001 0.001 0.001 0.12 17 30 b 37 c 46 c 45 b 57 c 70 c 69 b 86 b 92 b 112 c 99 b 129 135 302 b 722 b 1,025 b 0.24 19 32 ab 39 bc 52 b 53 a 71 b 85 b 74 a 95 a 105 a 128 a 110 a 138 144 351 a 794 a 1,145 a 0.36 19 34 a 44 a 55 ab 52 a 71 b 92 ab 71 ab 90 ab 97 b 123 ab 110 a 140 147 367 a 778 a 1,145 a 0.48 19 30 ab 43 ab 57 a 53 a 77 a 98 a 67 b 87 b 95 b 115 bc 101 b 133 145 377 a 743 a 1,120 a P 0.564 0.116 0.073 0.014 0.265 0.984 0.935 0.102 0.510 0.022 0.535 0.216 0.948 0.389 0.138 0.293 0.139 160 19 30 40 50 50 69 86 69 89 95 119 104 135 141 344 752 1,096 240 19 33 41 54 51 69 86 71 89 100 120 106 135 145 353 766 1,119 CV, % 15.1 10.4 10.7 11.5 10.0 12.5 14.1 7.8 7.4 8.0 8.1 7.2 7.5 11.0 10.4 6.8 6.8 TABLE 6. Excreta DM from broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed (%) A Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 7 7 14 1 14 P 0.316 0.957 0.227 0.012 0.001 0.001 0.001 0.020 0.939 0.465 0.040 0.648 0.836 0.057 0.001 0.378 0.005 0.12 30 33 33 30 a 33 a 33 a 29 a 31 a 30 29 28 ab 28 28 26 31 a 29 30 a 0.24 29 32 32 30 a 29 ab 30 ab 23 b 29 ab 29 27 26 b 27 28 28 29 ab 27 28 ab 0.36 31 33 31 24 b 27 b 27 bc 20 bc 27 b 30 28 27 ab 27 28 26 28 b 27 27 b 0.48 31 32 31 27 ab 26 b 26 c 18 c 27 b 30 29 29 a 28 27 26 27 b 28 27 b P 0.014 0.657 0.015 0.233 0.822 0.027 0.263 0.273 0.500 0.373 0.355 0.212 0.829 0.899 0.239 0.634 0.760 160 29 33 31 29 29 28 22 28 30 28 28 28 28 27 29 28 28 240 32 32 33 27 29 30 23 29 30 29 27 27 28 26 29 27 28 CV, % 9.5 6.7 9.2 17.4 13.2 12.0 20.3 11.2 7.4 10.3 8.2 10.0 12.0 8.3 8.3 8.5 7.1 B Excreta produced 24 h after placement.

368 TABLE 7. Broiler carcass DM as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed (%) A Item 4 d 7 d P 0.001 0.025 0.12 24.2 a 25.7 a 0.24 21.5 b 24.4 ab 0.36 21.2 b 24.6 ab 0.48 21.3 b 24.3 b P 0.009 0.315 160 22.6 24.6 240 21.6 24.9 CV, % 7.6 4.6 a,b Means within a column with no common superscript differ significantly (P < 0.05, by Tukey s test). A Means of two birds per replicate at 4 and 7 d. at 0.12% in the end of the first week (P < 0.001). On the other hand, increasing the DEB from 160 to 240 meq/kg lowered the number of deaths in that same period (Table 4). Both effects were independent and only remained while the birds were receiving the experimental feeds. Daily water intake increased with corresponding Na + concentration in the feeds. Analyses of JAPR: Research Report regression indicated that there was an increase in the amount of water individually consumed to the level of 0.45% Na + before reaching a plateau [19]. This response remained after the end of the first week and allocation to common feeds (0.20% Na +, 0.78% K +, 0.38% Cl ). Birds fed diets with DEB of 240 meq/kg showed a slightly higher water intake. However, this effect was not consistent only occurring on d 4 and 10 (Table 5). Responses to Na + and to DEB were independent. Increasing the concentration of sodium in the feed led to a reduction in the excreta DM. This effect was observed only after 4 d and remained until the day after removal of experimental feeds. Excreta DM, expressed as an average for the first 7 d, seemed not to reach a maximum response to inclusions of Na + [19]. Birds fed diets with the highest DEB showed an increase in the excreta DM. This, however, was an untimely response and only occurred on d 1, 3, and 6 (Table 6). Carcass DM at 4 d was increased with the 0.12% sodium feeds when compared with the feeds having sodium of 0.24% and greater (P < 0.001). Differences between the three highest Na + levels were not apparent when nominally ex- FIGURE 2. Total water intake and average excreta and carcass dry matter from broiler chicks from 1 to 7 d of age.

VIEIRA ET AL.: SODIUM REQUIREMENTS IN BROILER CHICKS 369 pressed (Table 7), but regressions estimated a plateau after 0.35% Na + [19]. Increasing the DEB to 240 meq/kg also produced a reduction in the carcass DM (P < 0.009), but as opposed to the Na + effects, this was seen only at 4dofage. Most requirements currently used for feed formulations are based on optimizations for BW gain and feed conversion. In the current study, Na + inclusion, which optimizes those responses, is, respectively, 0.38 and 0.40%. These are much higher than the current 0.20% Na + suggested by NRC [13] for feeds from 1 to 21 d of age, but they are in agreement with some previous results, suggesting that 0.20% Na + may be low for maximum performance [8, 11]. In general, recommendations for minerals follow the logic of higher requirements for younger birds. Therefore, it seems logical that requirements for Na + in the first week are higher than what is accepted as an average requirement from placement to 21 d of age. Mortality, expressed as a percentage, is usually a response with high variability. For this reason, significant differences of treatment effects for mortality are more difficult to obtain than for other performance responses, or are viewed skeptically when obtained. In this study, mortality was increased in birds fed the 0.48% Na + in feeds (P < 0.001), but a significant reduction was found (P < 0.001) when birds received the 240 meq/ kg feed during the first 4 d of age. Reduction in mortality has been related to low Na + intake [20]. Conversely, high concentrations of sodium chloride in feeds have been implicated with high blood pressure and mortality caused by sudden death syndrome [21]. Increased water intakes were correlated with corresponding water retention in carcasses and higher moisture in the excreta. These are all expected physiological compensations for high intakes of Na + and frequently occur with a reduction in the rate of glomerular filtration [22]. The current data showed water intake continuing to increase with corresponding increments in Na +. The same trend was seen with the moisture of excreta (especially on d 5 through 7) and with the whole carcass evaluation. However, each one of these measurements showed different levels of sodium to corresponding plateaus. Birds continued to increase water intake to 0.46% Na + in the feeds from 1 to 7 d of age. However, whereas maximization of water retained in their carcasses at 7 d of age occurred with 0.35% Na +, elimination of moisture in excreta increased linearly and did not reach a limit within the range of Na + used in this experiment, as illustrated in Figure 2. We observed that feed intake was positively correlated to water intake (P < 0.001) [23]. Therefore, the post-hatching requirements of Na + may also be seen as important to inducing greater water consumption and not only as a mineral needed to maintain normal metabolism. Nutritionists may be interested in the benefit from this relationship as a regular tool to increase feed intake in the first days after placement. CONCLUSIONS AND APPLICATIONS 1. Sodium requirements of broiler chicks in the first week post-hatching were higher than current NRC [13] recommendations for feeds from 1 to 21 d of age. Estimations of requirements obtained in this study, based on BW gain and feed conversion were between 0.38 and 0.40%. 2. Water consumption increased as a response to corresponding higher Na + in feeds reaching a maximum at 0.46% Na +. 3. Water consumption was highly correlated with increased feed intake, which represents a benefit for chick adaptation at placement. 4. DEB of 240 meq/kg improved overall performance of chicks when compared with that of 160 meq/kg. Effects were more prominent at 4dofage. 5. Mortality of broilers was increased when very high Na + was provided in the first week s feed; however, this was reduced when DEB of 240 meq/kg were used.

370 JAPR: Research Report REFERENCES AND NOTES 1. Burns, C. H., W. W. Cravens, and P. H. Phillips. 1953. The sodium and potassium requirements of the chick and their interrelationships. J. Nutr. 50:317 329. 2. Ross, E. 1977. Apparent inadequacy of sodium requirement in broiler chickens. Poult. Sci. 56:1153 1157. 3. Mongin, P. 1980. Role of sodium, potassium and chloride in eggshell quality. Pages 213 223 in Proc. Nutr. Conf. Florida. Univ. Florida, Gainesville, FL. 4. Ruiz-López, B., M. Rangel-Lugo, and R. R. Austic. 1993. Effects of selected minerals on acid-base balance and tibial dyschondroplasia in broiler chickens. Poult. Sci. 72:1693 1704. 5. Elzbieta, W., R. Rys, J. Koreleski, and M. Pietras. 1979. Effect of sodium chloride deficiency on basal metabolism in broiler chickens. Br. J. Nutr. 42:547 552. 6. Nott, H., and G. F. Combs. 1969. Sodium requirement of the chick. Poult. Sci. 48:660 665. 7. Edwards, H. M., Jr. 1984. Studies on the etiology of tibial dischondroplasia in chickens. J. Nutr. 114:1001 1013. 8. Britton, W. M. 1992. Effect of dietary salt intake on water and feed consumption of chicks. Pages 48-53 in Georgia Nutr. Conf. Proc., Atlanta, GA. Univ. Georgia, Athens, GA. 9. Murakami, A. E., S. E. Watkins, E. A. Saleh, J. A. England, and P. W. Waldroup. 1997. Estimation of the sodium and chloride requirements for the young broiler chick. J. Appl. Poult. Res. 6:155 162. 10. Barros, J. M. S., P. C. Gomes, L. F. T. Albino, and A. H. Nascimento. 1998. Sodium levels over performance parameters of broiler chickens from 1 to 21 days of age. Page 14 in Anais da Conferência APINCO 98 de Ciência e Tecnologia Avícolas. FACTA, Campinas, SP, Brazil. 11. Oviedo-Rondón, E. O., A. E. Murakami, A. C. Furlan, I. Moreira, and M. Macari. 2001. Sodium and chloride requirements of young broiler chickens fed corn-soybean diets (one to twenty-one days of age). Poult. Sci. 80:592 598. 12. National Research Council. 1984. Nutrient Requirements of Poultry. 8th ed. Natl. Acad. Press, Washington, DC. 13. National Research Council. 1994. Nutrient Requirements of Poultry. 9th ed. Natl. Acad. Press, Washington, DC. 14. Mongin, P. 1981. Recent advances in dietary anion-cation balance in poultry. Pages 109 119 in Recent Advances in Animal Nutrition. W. Haresign, ed. Butterworths, London, United Kingdom. 15. Mongin, P., and B. Sauveur. 1977. Interrelationships between mineral nutrition, acid-base balance, growth and cartilage abnormalities. Pages 235 247 in Growth and Poultry Meat Production. K. N. Boorman and B. J.Wilson, ed. British Poultry Science, Edinburgh, United Kingdom. 16. Hulan, H. W., P. C. M. Simons, P. J. W. Van Schagen, K. B. McRae, and F. G. Proudfoot. 1987. Effect of dietary cation-anion balance and calcium content on general performance and incidence of leg abnormalities of broiler chickens. Can. J. Anim. Sci. 67:165 177. 17. SAS Institute. 1998. SAS User s Guide: Statistics. Version 7.0 Edition. SAS Institute Inc., Cary, NC. 18. Steel, R. G. D., J. H. Torrie, and D. A. Dickey. 1997. Principles and Procedures of Statistics: A Biometrical Approach. 3rd ed. McGraw-Hill, New York, NY. 19. Feed conversion = 1.9583 X 2 1.6151 X + 1.4822; R 2 = 0.7079. BW gain = 320.87 X 2 + 241.23 X + 83.521; R 2 = 0.7808. Feed consumption = 182.53 X 2 + 122.44 X + 130.43; R 2 = 0.3226. Water consumption = 663.82 X 2 + 598.39 X + 242.09; R 2 = 0.6257. Excreta DM (average from 1 to 7 d) = 28.635 X + 30.993; R 2 = 0.6798. Carcass DM at 7 d = 26.153 X 2 18.653 X + 27.691; R 2 = 0.2255. 20. Manning, B., C. W. Nam, D. Zaviezo, M. B. Patel, and J. McGinnis. 1978. Dietary sodium levels and their influence on chick growth and feed conversion. Poult. Sci. 57:1153 (Abstr.). 21. Proudfoot, F. G., H. W. Hulan, and D. M. Nash. 1985. Effects of a wide range of dietary salt levels on the performance of broiler chickens. Can. J. Anim. Sci. 65:773 775. 22. Freeman, B. M. 1983. Physiology and biochemistry of the domestic fowl. Academic Press Inc., London, UK. 23. Correlation = 0.9961, P < 0.001.