Effects of an Ionophore Coccidiostat (Monensin or Salinomycin), Sodium or Potassium Bicarbonate, or Both, and Bacitracin Methylene Disalicylate in Broiler Chicken Diets

Efeitos do Coccídeostático lonóforo (Monensina ou Salinomicina), Bicarbonato de Sódio ou Potássio, ou Ambos, e Dissalicitato-Metileno de Bacitracina em Dietas para Frangos de Corte

Efeitos do Coccídeostático lonóforo (Monensina ou Salinomicina), Bicarbonato de Sódio ou Potássio, ou Ambos, e Dissalicitato-Metileno de Bacitracina em Dietas para Frangos de Corte

Effects of an Ionophore Coccidiostat (Monensin or Salinomycin), Sodium or Potassium Bicarbonate, or Both, and Bacitracin Methylene Disalicylate in Broiler Chicken Diets

Autor(es) / Author(s)

Hooge DM¹

Cummings KR²

McNaughton JL³

1 - Hooge Consulting Service, Inc., Eagle Mountain, Utah, USA

2 - Church & Dwight Co., Inc., Princeton, New Jersey (affiliated with Quimica Geral do Nordeste S/A – Carbonor, Camacari BA, Brasil)

3 - PARC Institute, Inc., Easton, Maryland, USA

Correspondência / Mail Address

Danny M. Hooge

8775 North Cedar Pass Road

Eagle Mountain, Utah 84043-3186

E-mail: [e-mail]

Unitermos / Keywords

bacitracina, coccidiose, coccidiostático ionóforo, bicarbonato de sódio, bicarbonato de potássio

bacitracin, coccidiosis, ionophore coccidiostat, potassium bicarbonate, sodium bicarbonate

Observações / Notes

BMD^R is a registered trademark of Alpharma, Inc., Fort Lee, New Jersey, USA for bacitracin methylene disalicylate.

RESUMO

Pintos Peterson x Arbor Acres foram criados em camas usadas até 45 ou 46 dias de vida em três testes de aviário. Inoculações de coccídea foram dadas pela água na idade de 14 dias. O bicarbonato de sódio (BCS; 0.20%) ou bicarbonato de potássio (BCP; 0.14%) foi adicionado à dieta dos frangos contendo monensina (MON; 110 mg/kg) ou salinomicina (SAL; 66 mg/kg) no Experimento 1.

No Experimento 2, usando SAL (55 mg/kg), três tratamentos de dieta de bicarbonato (SBC, 0.20%; PBC, 0.20%; ou SBC + PBC 0.10% cada) foram testados com ou sem BMD^R (55 mg/kg).

Dietas que diferem em níveis de SAL, BMD^R e SBC foram avaliados no Experimento 3.

Interação benéfica foi encontrada entre ionóforos e bicarbonatos para a mortalidade (menor no caso de BCS ou BCP e MON) no Experimento 1. Para efeitos principais, no Experimento 1 BCP com MON ou SAL melhorou o peso corporal, a taxa de conversão de alimento e a mortalidade. SAL melhorou o peso, a taxa de conversão de alimento e a mortalidade comparado com MON. No Experimento 2, BCP com SAL melhorou o peso, arranhões devidos a lesão coccídea, taxa de conversão de alimento e mortalidade através de dois níveis de BMD^R. O BCP e BCS foram ambos eficazes no Experimento 1, mas BCP foi aproximadamente 0 a 40% tão efetivo quanto o BCS, dependendo do parâmetro no Experimento 2. A metade de níveis de BCS mais BCP geralmente apresentava resultados intermediários entre o controle e o BCS. BCS com MON ou SAL diminuíram a mortalidade, os arranhões devidos a lesão coccídea e taxas de conversão de alimento (Experimentos 1 e 2), e aumentou o peso corporal (Experimento 2).

No Experimento 3, BMD^R em todos os alimentos melhorou o peso corporal e a conversão de alimento contra o alimento inicial apenas, e BCS com SAL e BMD^R melhoraram todos os parâmetros de desempenho.

ABSTRACT

Peterson x Arbor Acres chicks were grown on used litter to 45 or 46 days of age in three pen trials. Coccidial inoculations were given by water at 14 days of age. Sodium bicarbonate (SBC; 0.20%) or potassium bicarbonate (PBC; 0.14%) was added to broiler chicken diets containing monensin (MON; 110 mg/kg) or salinomycin (SAL; 66 mg/kg) in Experiment 1.

In Experiment 2, using SAL (55 mg/kg), three dietary bicarbonate treatments (SBC, 0.20%; PBC, 0.20%; or SBC + PBC 0.10% each) were tested with or without BMD^R (55 mg/kg).

Diets differing in SAL, BMD^R, and SBC levels were evaluated in Experiment 3.

Beneficial interaction was found between ionophores and bicarbonates for mortality (lower when SBC or PBC and MON) in Experiment 1. For main effects, in Experiment 1 PBC with MON or SAL improved body weight, feed conversion ratio and mortality. SAL improved weight, feed conversion ratio and mortality compared to MON. In Experiment 2, PBC with SAL improved weight, coccidial lesion score, feed conversion ratio and mortality across two levels of BMD^R. The PBC and SBC were equally effective in Experiment 1, but PBC was about 0 to 40% as effective as SBC, depending on parameter in Experiment 2. Half levels of SBC plus PBC generally gave intermediate results between control and SBC. SBC with MON or SAL lowered mortalities, coccidial lesion scores, and feed conversion ratios (Experiments 1 and 2), and increased body weight (Experiment 2).

In Experiment 3, BMD^R in all feeds improved body weight and feed conversion versus in starter feed only, and SBC with SAL and BMD^R improved all performance parameters.

INTRODUCTION

Dietary sodium bicarbonate (SBC) contains 27.1% sodium and 71.9% bicarbonate. Adding SBC and an ionophore coccidiostat to the feed of broiler chickens grown on built-up litter and with or without an additional coccidial challenge has been reported to significantly improve final body weight, feed efficiency, coccidial lesion score, livability, and carcass yield compared to controls. Optimal levels of SBC were determined to be 0.20 to 0.30% for continuous feeding during all phases of broiler chicken growth and across all seasons (Hooge et al., 1999ab), except during heat stress which may require higher levels of 0.40 to 1.70% (Phelps, 1992; Teeter et al., 1985; Merrill, 1993; Balnave & Gorman, 1993). It has been concluded from two recent unpublished pen trials by the authors with Ross x Ross or Cobb x Cobb broilers that 0.3 and 0.4% levels of SBC were considerably more effective than 0.2% for improving productive and processing performance of modern high meat yield birds.

Feed-grade SBC contains very low levels of chloride (<150 mg/kg), compared to 60% chloride in salt (NaCl; sodium chloride), and therefore can be used as a partial replacement for NaCl or to provide extra sodium without increasing the chloride in the diet or the body. The addition of 0.2, 0.3, or 0.4% dietary sodium bicarbonate on top of regular feed results in significant linear decreases in litter moisture, as well as improved bird performance, based on recent unpublished data by the authors.

Augustine (1997) at the USDA Avian Coccidiosis Lab in Beltsville, Maryland discovered that dietary SBC in the absence of a coccidiostat substantially increased the number of sporozoites in cross-sectional intestine (E. acervulina, +48%; E. maxima, +68%) following inoculation compared to results with inoculated control birds. With SBC plus MON (121 mg/kg), intestinal E. acervulina sporozoite counts were increased by 6.4% and E. maxima developmental stages were increased by 104%, compared to results for the MON diet without SBC. The enhancing effect of dietary SBC on coccidial invasion has been associated with improved broiler performance, but whether the effect is due to sodium, bicarbonate, or both has not been determined.

Feed-grade PBC is composed of 38.7% potassium and 60.3% bicarbonate. It is more expensive than SBC on a weight basis, but requires only 70% as much product to provide an equal amount of cation (e.g., 1.0 kg SBC and 0.7 kg PBC each contribute 0.271 kg of sodium or potassium, respectively). In the United States, PBC is a Food and Drug Adminsitration approved (Code of Federal Regulations, Title 21, 582.1613) "generally recognized as safe" feed ingredient. It may have practical application when potassium levels are lower than normal due to decreased soybean meal levels resulting from: high soybean meal prices; formulation for lower protein, synthetic amino acid fortified broiler feeds; or replacement of soybean meal with animal byproduct sources.

Jensen (1982) reported that adding extra sodium (0.10%) from NaCl was without effect in counteracting the growth depressing action of a high level of MON. In another experiment, either SBC (0.65%, most effective) or PBC (0.53%, second in effectiveness) significantly improved four-week broiler chick body weights with high MON (160 mg/kg), but NaCl (0.45%) did not.

Nesheim et al. (1964) concluded that "in the formulation of purified diets for chicks ... supplemented with arginine-HCl, the sodium and potassium in the mineral mixture should supplied as carbonate or bicarbonate salts". Using PBC at a level in a chick diet sufficient to alleviate a lysine-arginine antagonism (1.8% potassium), Riley & Austic (1984) found that a more alkaline feed resulted, but no significant changes were observed in the intestinal tract contents, from the crop to the distal small intestine. Crop pH with PBC was numerically higher than results for the unsupplemented diet group (crop pH 6.88 versus 6.60 for controls). Fancher & Jensen (1989) observed no significant improvement in broiler chicken performance from 21 to 42 d of age using reduced crude protein, amino acid supplemented diets with PBC added to equalize the potassium levels with normal protein level control diets. However, the plasma potassium level significantly increased compared to control results without PBC.

The purpose of this research was to evaluate dietary SBC bicarbonate and to compare the efficacy of PBC to SBC in broiler diets containing an ionophore (MON or SAL), with or without BMD^R, when chicks are grown on built-up litter and given a coccidial challenge.

MATERIAL AND METHODS

Two broiler chicken litter-floor pen trials were conducted at PARC Institute, Inc., Easton, Maryland with combined sexes of Peterson x Arbor Acres chicks during the periods of August 25 to October 9, 1992 (Experiment 1) and January 7 to February 22, 1993 (Experiment 2). The chickens were grown on built-up litter with a covering of new litter (after removal of wet, "caked" material) to expose them to a "natural" coccidial challenge. Birds were grown in facilities that were well insulated, power ventilated with wall fans, and electrically lighted (continuous). Warm-room brooding was used during the starting periods.

All chicks were vaccinated for Mareks disease, Newcastle disease, and infectious bronchitis at the hatchery. Each replicate pen contained 88 or 90 chicks at placement (0.069 or 0.067 m²/bird), and at placement, chicks were considered one day of age. Each chick that died during the first seven days of a trial was replaced with a bird of the same sex from the same shipment. No chicks were replaced after noon on day seven. Mortality was recorded daily.

In these 1992 and 1993 experiments, corn-soy-meat feeds were formulated to meet National Research Council (1984) nutrient requirements because the National Research Council (1994) recommendations had not been published. Calculated protein (%) and metabolizable energy (kcal/kg) levels in starter, grower, and finisher basal diets were: 23.68, 3200; 21.78, 3230; and 19.00, 3250.

The National Research Council (1984) requirements for sodium and chloride were each 0.15% for all broiler feeds, and potassium minimums were 0.40%, 0.35%, and 0.30% in starter, grower, and finisher phases, respectively. The National Research Council (1994) requirements for sodium and chloride were 0.20%, 0.15%, and 0.12% in the three feed phases whereas the requirement for potassium was 0.30% in all feeds. In Experiments 1 and 2, the calculated sodium contents of basal diets were: starter, 0.18% (exceeding NRC 1984 of 0.15%, but slightly below the NRC 1994 recommendation of 0.20%); grower, 0.16%; and finisher, 0.15%. Calculated chloride levels were: starter, 0.27%; grower, 0.24%; and finisher, 0.25%. Calculated potassium contents were: starter, 0.84%; grower, 0.73%; and finisher, 0.65%. Dietary electrolyte balances calculated as Na+K-Cl, mEq/kg, in basal diets were: starter, 217; grower, 189; and finisher, 161.

Starter feeds were crumbled and fed from 0 to 21 days of age. Grower feeds were pelleted and fed from 21 to 40 or 41 days of age. Finisher feeds were pelleted and fed from 40 or 41 days to 45 or 46 days of age in the different tests. In all cases, SBC, PBC, or both, were added "on top" of practical type basal formulas, adding to each batch weight, rather than being "formulated in".

Feed consumptions were determined by pens at the end of the starter and finisher feed phases. Feed conversions were calculated. Adjusted feed conversions have been reported in some cases, and these were determined by adding the weight of removed and dead birds to total live weight and dividing this into the total feed consumed.

In all three experiments chicks were challenged at 14 days of age through the drinking water with three species of live coccidia. The approximate numbers of oocysts given per bird were: E. acervulina 100,000, E. maxima, 50,000, and E. tenella 10,000. Coccidiosis lesion scores were taken at 21 days of age in Experiment 2 only. At least four birds, two males and two females, in each pen were visually scored by looking at the upper small intestine, middle small intestine, lower small intestine, and ceca. These locations were totalled for a composite score per bird. The five point system, 0 to 4, was used for scoring, with categories as follows: 0 = normal, 1 = slight lesions, 2 = moderate lesions, 3 = severe lesions, and 4 = extremely severe lesions (Johnson and Reid, 1970).

Experiment 1

A 2 x 3 factorial arrangement with six dietary treatments and 10 replicate pens of 88 birds each (44 males and 44 females) per treatment (ionophores x bicarbonates) was used. Treatments consisted of two ionophore coccidiostats (MON, 110 mg/kg; and SAL, 66 mg/kg) and three bicarbonate treatments (control 0%, SBC 0.20%, and PBC 0.1401%). The 0.20% level of SBC bicarbonate provided 0.0542% added sodium whereas the 0.1401% level of PBC gave 0.0542% added potassium. Therefore, sodium and potassium were assessed in these treatments on an equal weight basis rather than on a milliequivalence basis. The bicarbonate contributions were different, however. BMD^R was included at 55 mg/kg in all feeds.

Experiment 2

A 2 x 4 factorial arrangement with eight dietary treatments (BMD^R x bicarbonates) and 10 replicate pens with 96 combined-sex birds (48 males and 48 females) each per treatment was utilized. There were two levels of BMD^R (0 or 55 mg/kg) in grower and finisher feeds and four levels of sodium sources (basal control, +0.20% SBC, +0.20% PBC, or +0.10% SBC and 0.10% PBC). Two male and two females per pen were sampled and scored for coccidial lesions at 21 days of age.

Experiment 3

Experiment 3 ran concurrently with Experiment 2 and utilized four treatments from Experiment 2 and two additional treatments with a higher level of SAL. Experiment 3 was analyzed as a 2 x 3 factorial arrangement with six treatments and 10 replicate pens with 96 combined-sex birds (48 males and 48 females) per treatment. BMD^R was fed at 55 mg/kg in all starter diets. Six dietary treatments included two SBC levels (0 or 0.20%) and three combinations of SAL in all feeds and BMD^R in the grower and finisher feeds were as follows: 1) SAL, 55 mg/kg, and BMD^R, 0 mg/kg; 2) SAL, 55 mg/kg, and BMD^R, 55 mg/kg; and 3) SAL, 66 mg/kg, and BMD^R, 55 mg/kg.

Data were subjected to ANOVA procedures according to experimental designs to detect any significant effects. Arc sine transformations of raw data were performed for mortalities and coccidial lesion scores prior to analysis. When effects were found by ANOVA to be significant for a parameter, and there were more than two means in a group, means were separated by Tukey's HSD Procedure (p < 0.05). The statistical software Statistix^R for Windows (1996) was used to make arc sine transformations, to perform ANOVA, and to separate means by computer.

RESULTS

Experiment 1

Birds were grown on built-up litter, offering a natural coccidial challenge, and were given a coccidial inoculation through the drinking water at 14 days of age (see Table 1). A significant (p < 0.05) interaction was found between ionophores and bicarbonates for 0 to 45 days mortality, and the MON treatment without SBC or PBC had higher mortality than all other treatments (16.43%vs 6.67 to 9.05%).

For main effects, SAL significantly (p < 0.05) increased 45-day body weight and lowered feed conversion ratio and mortality compared to MON. The SBC diets significantly (p < 0.05) reduced feed conversion ratio and mortality compared to the basal diets without SBC.

The PBC diets significantly (p < 0.05) increased final body weight and lowered feed conversion ratio and mortality compared to the control diets without PBC. No sigificant performance differences were found between SBC and PBC.

Experiment 2

This trial was on built-up litter, with an initial covering of new litter, and a coccidial inoculation at 14 days of age was used as a stressor. Based on 46-day productive performance and coccidial lesion scores, there were no significant interactions between the antibiotic bacitracin methylene disalicylate (BMD^R) and bicarbonate sources for any parameters measured (see Table 2).

Regarding main effects, BMD^R at 55 mg/kg in starter, grower, and finisher diets significantly (p < 0.05) increased 46-day body weight and reduced feed conversion ratio compared to the treatment receiving BMD^R in the starter feed only. Dietary SBC at 0.20% significantly (p < 0.05) increased body weight and lowered coccidial lesion scores, mortality-adjusted feed conversion ratio, and mortality compared to the control diets without SBC. Adding SBC at 0.10% and PBC at 0.10% of the diets significantly (p < 0.05) reduced coccidial lesion scores, mortality-adjusted feed conversion ratios, and mortality compared to diets without these bicarbonate supplements. Results with the half levels of SBC plus PBC were intermediate between control and SBC treatment values. Supplementation with PBC at 0.20% gave results that were not significantly different from those of the unsupplemented control basal diets.

Experiment 3

Results of this 2 x 3 factorial arrangement study are presented in Table 3. No significant interaction effects were observed between SAL/BMD^R and bicarbonates for any parameters.

Regarding main effects, with dietary SAL at 55 mg/kg and BMD^R at 55 mg/kg in all feeds significantly (p < 0.05) increased body weight and reduced coccidial lesion score and feed conversion ratio compared to SAL in all feeds and BMD^R. The coccidial lesion score was lowered slightly (2.725 vs 2.612) but significantly, indicating a small protective effect against coccidial lesions with dietary BMD^R in all feeds versus starter only. When using SAL at 66 mg/kg, supplementing all feeds with BMD^R produced significantly (p < 0.05) heavier body weight and lowered coccidial lesion score and feed conversion ratio compared to BMD^R in the starter diet only. The coccidial lesion score for the treatment group receiving dietary SAL 66 mg/kg and BMD^R in all feeds was significantly (p < 0.05) lower than SAL diets with BMD^R in starter feeds only.

Considering main effects for SBC (0 or 0.20%), adding SBC at 0.20% to the basal diets with various combinations of SAL and BMD^R significantly (p < 0.05) improved all performance parameters. The largest improvements, percentagewise, due to dietary SBC were in mortality and coccidial lesion score.

DISCUSSION

Three pen trials were conducted during the periods of August to October (summer and fall) and January to February (winter) using Peterson Arbor Acres broiler chicks on built-up litter and given a coccidial challenge with three Eimeria species (acervulina, maxima, and tenella). Dietary SBC was evaluated at 0 or 0.20% levels in comparison to PBC at 0 or 0.14% (Experiment 1) or 0.20% (Experiment 2). In Experiment 2, SBC and PBC were also added at 0.10% levels each. In Experiment 3, dietary SBC was added at 0.20% to each of three basal diets with various combinations of SAL and BMD^R and compared to each of these series of diets unsupplemented with SBC. Results with 0.20% dietary SBC were similar to those reported previously by Hooge et al. (1999a,b) with regard to significant (p <0.05) increases in final body weight at 45 or 46 days, and in reductions in coccidial lesion scores, mortality-adjusted feed conversion ratio, and mortality compared to controls without SBC.

The mode of action by which dietary SBC improves broiler productive performance is not known. Augustine (1997) demonstrated that dietary SBC enhances invasion of coccidia into the intestinal epithelium of broiler chicks, with or without MON, and this phenomenon is associated with improvements in live performance. Therefore, SBC has a potentiating or synergistic effect when used in combination with ionophores. Whether these benefits are due to sodium, bicarbonate, or both, is not known.

Dietary PBC provided potassium and bicarbonate. The PBC was compared at dietary levels of 0.14% or 0.20% to SBC at 0.20% in Experiments 1 and 2, respectively. In Experiment 1, PBC was equally efficacious with SBC, but in Experiment 2, PBC was only about 0 to 40% as effective as SBC, depending on parameter considered. There was no special adantage to using SBC at 0.10% plus PBC at 0.10% in broiler diets containing SAL at 55 mg/kg; coccidial lesion scores and mortalities were generally intermediate between control and SBC (0.20%) treatment results.

Nesheim et al. (1964) suggested that purified chick diets be supplemented with PBC to help neutralize acidity caused by chloride molecules attached to some of the amino acids (for example, L-lysine HCl). In practical-type diets such as those utilized in these pen trials, there would not be as much need for a buffer as in purified diets, unless the feeds were supplied with excess quantities of chloride, sulfate, or phosphate, or combinations of these, from various ingredients.

Riley & Austic (1984) observed that 1.8% dietary PBC was sufficient to alleviate a lysine-arginine antagonism which depressed growth, but the levels of PBC in the experiments described herein did not exceed 0.20%. Fancher & Jensen (1989) did not obtain any significant differences in performance of broiler chickens given feeds supplemented with PBC to bring the levels of potassium in amino acid formulated feeds up to those of regular control diets.

Bacitracin methylene disalicylate (BMD^R) at 55 mg/kg in broiler starter, grower, and finisher feeds significantly (P < 0.05) improved body weight and mortality-adjusted feed conversion ratio compared to 55 mg/kg in starter feed only. Although this antibiotic has been utilized for many years, its continuing efficacy has been demonstrated. Interestingly, BMD^R in all feeds reduced coccidial lesion scores compared to its use in starter only. This antibiotic is considered to have no effect against coccidia but acts beneficially to minimize secondary infections.

A SAL level of 66 mg/kg was shown to significantly (p < 0.05) reduce coccidial lesion score compared to SAL at 55 mg/kg. This allows flexibility regarding the use levels of SAL over its legal range of supplementation under commercial situations to protect against different levels of coccidial challenge and severity of coccidiosis. It was concluded that dietary SBC (0.20%) in combination with either MON (55 mg/kg) or SAL (55 or 66 mg/kg), and BMD^R (55 mg/kg) in all feeds, gave the greatest benefits under the conditions of these experiments.

References

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Publication Dates

• Publication in this collection
  06 June 2003
• Date of issue
  Apr 2000