Sodium Requirements for the First Seven Days in Broiler Chicks

Transcription

1 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 , 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: 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.

2 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.

3 364 JAPR: Research Report TABLE 1. Composition of experimental feeds (%) Sodium (%) DEB = 160 meq/kg DEB = 240 meq/kg Ingredient 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 Sodium chloride Calcium chloride Potassium carbonate Kaolim 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 Potassium 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

4 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 d d 1 42 d Dietary Na, % P b 154 b , c 65 b 107 b ,707 2, a 171 a , b 74 a 125 a ,652 2, a 170 a , ab 71 a 124 a ,683 2, a 169 a , a 69 a 126 a ,666 2,480 P , ,688 2, , ,667 2,478 CV, % B Na DEB (P < 0.03): = 87; = 90; = 95; = 100; = 101; = 99; = 95; = 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 d d 1 42 d 1 4 d 4 7 d 1 7 d 7 14 d d d 1 42 d P b 142 b 362 b 602 3,427 4, c b a 150 a 387 a 622 3,426 4, b a a 150 a 382 a 604 3,426 4, ab a a 147 a 385 a 618 3,554 4, a a P ,472 4, ,445 4, CV, %

5 366 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 P NS c c b b c c a a P NS CV, %

6 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 P b 37 c 46 c 45 b 57 c 70 c 69 b 86 b 92 b 112 c 99 b b 722 b 1,025 b ab 39 bc 52 b 53 a 71 b 85 b 74 a 95 a 105 a 128 a 110 a a 794 a 1,145 a a 44 a 55 ab 52 a 71 b 92 ab 71 ab 90 ab 97 b 123 ab 110 a a 778 a 1,145 a ab 43 ab 57 a 53 a 77 a 98 a 67 b 87 b 95 b 115 bc 101 b a 743 a 1,120 a P , ,119 CV, % TABLE 6. Excreta DM from broilers as influenced by sodium level and dietary electrolyte balance (DEB) in the first week s feed (%) A Days P a 33 a 33 a 29 a 31 a ab a a a 29 ab 30 ab 23 b 29 ab b ab ab b 27 b 27 bc 20 bc 27 b ab b b ab 26 b 26 c 18 c 27 b a b b P CV, % B Excreta produced 24 h after placement.

7 368 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 a 25.7 a b 24.4 ab b 24.6 ab b 24.3 b P CV, % 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.

8 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 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.

9 370 JAPR: Research Report REFERENCES AND NOTES 1. Burns, C. H., W. W. Cravens, and P. H. Phillips The sodium and potassium requirements of the chick and their interrelationships. J. Nutr. 50: Ross, E Apparent inadequacy of sodium requirement in broiler chickens. Poult. Sci. 56: Mongin, P Role of sodium, potassium and chloride in eggshell quality. Pages in Proc. Nutr. Conf. Florida. Univ. Florida, Gainesville, FL. 4. Ruiz-López, B., M. Rangel-Lugo, and R. R. Austic Effects of selected minerals on acid-base balance and tibial dyschondroplasia in broiler chickens. Poult. Sci. 72: Elzbieta, W., R. Rys, J. Koreleski, and M. Pietras Effect of sodium chloride deficiency on basal metabolism in broiler chickens. Br. J. Nutr. 42: Nott, H., and G. F. Combs Sodium requirement of the chick. Poult. Sci. 48: Edwards, H. M., Jr Studies on the etiology of tibial dischondroplasia in chickens. J. Nutr. 114: Britton, W. M Effect of dietary salt intake on water and feed consumption of chicks. Pages 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 Estimation of the sodium and chloride requirements for the young broiler chick. J. Appl. Poult. Res. 6: Barros, J. M. S., P. C. Gomes, L. F. T. Albino, and A. H. Nascimento 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 Sodium and chloride requirements of young broiler chickens fed corn-soybean diets (one to twenty-one days of age). Poult. Sci. 80: National Research Council Nutrient Requirements of Poultry. 8th ed. Natl. Acad. Press, Washington, DC. 13. National Research Council Nutrient Requirements of Poultry. 9th ed. Natl. Acad. Press, Washington, DC. 14. Mongin, P Recent advances in dietary anion-cation balance in poultry. Pages in Recent Advances in Animal Nutrition. W. Haresign, ed. Butterworths, London, United Kingdom. 15. Mongin, P., and B. Sauveur Interrelationships between mineral nutrition, acid-base balance, growth and cartilage abnormalities. Pages 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 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: SAS Institute 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 Principles and Procedures of Statistics: A Biometrical Approach. 3rd ed. McGraw-Hill, New York, NY. 19. Feed conversion = X X ; R 2 = BW gain = X X ; R 2 = Feed consumption = X X ; R 2 = Water consumption = X X ; R 2 = Excreta DM (average from 1 to 7 d) = X ; R 2 = Carcass DM at 7 d = X X ; R 2 = Manning, B., C. W. Nam, D. Zaviezo, M. B. Patel, and J. McGinnis 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 Effects of a wide range of dietary salt levels on the performance of broiler chickens. Can. J. Anim. Sci. 65: Freeman, B. M Physiology and biochemistry of the domestic fowl. Academic Press Inc., London, UK. 23. Correlation = , P <