Evaluation of three feeding programs for broilers based on sorghum-soybean diets with different protein percentages

Current broiler growth rate is partly the result of an intense genetic selection;¹ therefore, feeding is important to achieve the maximum productive expression. Success attained until now in this practice has been due to better knowledge of the functions that different nutriments carry out, which in turn allows higher precision when establishing nutrimental needs.² To be able to feed chickens, a knowledge of the feeding phases or stages is required to be able to cover nutrimental requirements.³ Conversely, the need for nutriments in broiler feeding is changing due to genetic advances that are constantly been promoted by the different genetic companies that have achieved bird lines that increase standard weight by 50 g per year, which represents one less day in the rearing cycle.⁴

Feeding stages or phases are the different divisions that are established in order to obtain maximum utilization of feed and nutriments. These divisions are based on physiological and metabolic processes in the animal; their objective being to provide the bird with the amount of necessary nutriments at a certain age, in order to avoid over-feeding and waste.^5-7 Formulation based on the concept of ideal protein, has as objective the optimization of amino acids levels in farm feeding. With this formulation method, balanced feed must be prepared using digestible amino acids values that provide the ingredients and nutrimental requirements of the animal.^8,9 Protein in the diet is used by the chickens for many functions, and the most important one is muscle synthesis.¹⁰ It is known that chickens require in the diet a specific amount of essential amino acids and a sufficient amount of nitrogen for the synthesis of nonessential amino acids and not just crude protein per se. ¹¹ A lower concentration of protein may be used in diets through the use of crystalline amino acids that are found in the market, such as methionine, lysine, threonine and tryptophan, benefiting the environment where the animals are confined, since excreta are generated that have a lower nitrogen concentration and lower ammonia production, which in turn causes an economic benefit by reducing the protein content of rations.¹²

Likewise, most of the studies carried out in this matter have been carried out in chickens fed corn-soybean diets, when in Mexico a large portion of poultry balanced feeds are sorghum-soybean meal, with the inclusion of synthetic amino acids to be able to use alternative ingredients such as meat with bone meal and corn gluten meal and therefore, it is required that more information related to this be generated.

Taking this background into consideration, this study was carried out in order to evaluate productive yield in broilers fed with three different programs (2, 3 or 4 feeds), and diets with different protein percentages in each feeding stage, but with similar amounts in the most limiting amino acids content (lysine, methionine, threonine, tryptophan and arginine), in sorghum-soybean meal diets with or without meat with bone meal and corn gluten meal inclusion.

 

Research was carried out at the Centro de Enseñanza, Investigacion y Extension en Produccion Avicola (CEIEPAv) of the Facultad de Medicina Veterinaria y Zootecnia of the Universidad Nacional Autonoma de Mexico, located on Salvador Diaz Miron number 89, in Colonia Santiago Zapotitlan, Delegacion Tlahuac, Distrito Federal, at an altitude of 2240 masl, 19°15´ North latitude and meridian 99° 02’ 30” West longitude; under sub-humid (Cw) temperate climate conditions; January is the coldest month and May the warmest, with an annual average temperature of 16°C and 747 mm annual rainfall.¹³ In both experiments, six treatments with three replicates of 30 birds each were evaluated; using 1 to 49 days of age Ross 308 chickens from a commercial hatchery. The vaccination schedule consisted in the application of the combined emulsion NewcastleAvian Influenza vaccine (0.5 ml/bird) and another of modified live virus against Newcastle (1 drop in eye per bird) at 10 days of age.

Rearing was carried out on floor with wood shavings, in a natural environment house and feeding by free access to meal. In Experiment 1, diets were used based on sorghum-soybean with and without reduction of 2 percentile units of protein and in Experiment 2, meat meal and maize gluten were included. In both experiments the diets had synthetic amino acids added: in Experiment 1, lysine, methionine and threonine; in Experiment 2, lysine, methionine, threonine, tryptophan and arginine. A protein and amino acid analysis of the ingredients to be used in the diets was carried out before their formulation, ¹⁴ as indicated by the National Research Council (NRC).3 Digestibility coefficients published by Mariscal et al¹⁵ were used to estimate the digestible amino acids of the diets. Birds were randomly assigned in each experiment in six treatments with three replicates of 30 chickens each, in the following manner:

For the two phase feeding program starting feed was used from 0 to 21 days and another finishing feed from 22 to 49 days of age. The three-phase program had starting feed from 0 to 21 days, growth feed from 22 to 42 days and finishing feed from 43 to 49 days of age. In the four-phase program pre-initiation feed was used from 0 to 7 days, starting feed from 8 to 21 days, growth feed from 22 to 35 days and finishing feed from 36 to 49 days of age. In Table 1, used protein and metabolizable energy (ME) levels are shown for each feeding phase of the six treatments and in Table 2, the digestible amino acid profiles in ideal protein base are shown. In Experiment 1, diets were based on sorghum and soybean paste, and in Experiment 2, besides sorghum and soybean meal, 4% meat with bone meal and 0.7 to 3.7% corn gluten meal were added.

Access to feed and water was ad libitum. Records were kept of weight gain, feed consumption and feed conversion. At the end of the study, 15 birds of each treatment were subjected to fasting and were slaughtered in a commercial slaughterhouse (5 from each replicate). Birds were weighed before slaughter and carcasses were weighed without head, legs and viscera. Also, the breast with bone, leg and thigh were weighed to estimate yield. Likewise, 300 g ground carcass samples were randomly taken from each replicate for analysis by the method indicated in the Association of Official Analytical Chemists method (AOAC),¹⁶ by Kjieldahl method for total protein and fat with diethyl ether as solvent.

In both experiments, a completely random design with factorial arrangement 2 x 3 was used, where one factor were the diets with or without 2% protein reduction and the other factor the three feeding programs with 2, 3 and 4-phases that were used to analyze body weight, feed conversion, weight gain, body fat deposits, abdominal fat deposits, carcass yield, breast yield, and leg and thigh yield. Since there was not interaction between both factors, comparisons between treatments of main effects were made by Tukey’s test; for statistical analysis the SPSS version 17 was used.¹⁷

 

 

In Table 3 it can be observed that weight gain at 49 days of age was similar (P > 0.05) for the diet factor and for the feeding phase factor. Accumulated feed conversion was similar (P > 0.05) between high and low protein diets; nevertheless, feed conversion was different (P < 0.05) for the feeding phase factor, since it was better when the chickens were fed in four feeding phases.

In relation to carcass yields: breast, leg with thigh, as well as amount of protein and fat deposited in the carcass, there were no statistically significant differences between factors and there was no interaction effect (Table 3).

In Table 4 it can be observed that weight gain and feed conversion at 49 days of age were similar (P < 0.05) for both factors. No statistical differences were found in any of the factors and there was not an interaction effect for carcass, breast, leg and thigh yield, as well as the amount of deposited protein and total fat.

 

The results obtained in experiments 1 and 2 for productive behavior did not show differences in the use of high and low protein diets, indicating that the use of synthetic amino acids allows the reduction of protein levels in diets.^8,12 Results of this study partly coincide with those obtained by some authors1,2 that found that the addition of synthetic amino acids (methionine, lysine, threonine, arginine, tryptophan, isoleucine and valine) in reduced protein diets for broilers, did not affect productive and carcass yields, as was observed in this research, with the exception of the addition of isoleucine and valine amino acids. Likewise, in relation to feeding systems, the use of four feeds for broilers allowed an optimum coverage of the nutriments necessary at specific ages, in order to avoid waste and overfeeding; in other words, nutriment consumption is reduced and excretion is lower.^5,18,19

Productive behaviors were similar according to the data obtained in productive response, carcass yield, protein content and fat in chickens fed during the two, three and four feeding phases, with high protein diets and diets reduced by 2 percenile units of protein for each phase, with the most limiting amino acids added. Baker9 and Terrazas et al.20 indicated that ideal protein formulation allows the use of various ingredients for poultry without detriment to productive variables.

Formulation with digestible amino acids based on ideal protein and the inclusion of crystalline food grade amino acids allows the reduction of protein ingredient use while covering the nutrimental needs of with lower nitrogen content, and also there is a reduction in the cost of feeding.^5,10,22

The four feeding phase system gave a better coverage of nutrient needs of chickens when compared to chickens fed with two or three feeding phases, as is mentioned by some researchers.^21,23,24 The favorable results obtained in the productive cycle of the chicken in both experiments indicate that the reduction of protein concentration in feeding programs with the use of synthetic amino acids is beneficial. Experiments with broilers have shown that it is feasible to reduce from the diet four percentile points of the level suggested by the NRC3 in birds that are 0 to 3 and 3 to 6 weeks of age. Likewise, the low protein diet has as limiting amino acids methionine and lysine, and at a lesser degree, arginine, valine and threonine, demonstrating that the productive response of chickens was similar with both experimental diets.^5,10,22 In relation to the growth stage, the level of protein (20%) recommended by the NRC,3 was evaluated comparing with the response of other birds that received a diet with 16% of this nutriment; at the end, there were no differences in productivity of chickens between treatments. Data from this study coincide with those of other researchers that have found that the use of methionine, lysine, threonine, arginine and tryptophan in low protein diets and formulated under the ideal protein concept, does not have a negative effect on growth and that the diet cost can be reduced.^10,25,26 According to the information generated in this experimental study with sorghum-soybean meal based diets and using the criteria of ideal protein, formulating a digestible amino acid profile allows the use of ingredients such as meat with bone meal (4%) and corn gluten meal (0.7 to 3.7%), with a uniform productive yield in the chickens; there is already available reliable information on the digestibility value of amino acids of an important number of raw materials.¹⁵

It is important to underline that even though there was no statistical difference in final weight and yield of the carcasses of chickens fed with 2, 3 and 4 feeding phases programs in experiments 1 and 2, in Experiment 1, feed conversion was statistically better when birds were fed in 4 phases, either with high or low protein diets. Some studies, indicate that 4 feeding phases are closer to covering nutrimental needs according to the age of the chicken and their performance is higher.²⁴ This is probably due to the fact that as more phases are used for finishing broilers, the better the required nutritional profile is covered achieving economic balance, that may optimize costs for the broiler industry enterprises and allow the use of alternative ingredients without causing nutrimental deficiencies in the birds.^1,22

With the results obtained in this study, it can be 308 concluded that the formulation based on ideal protein allows the use of lower quality ingredients in diet formulas for poultry, without detriment to their productive variables. The productive response, carcass yield, protein content and fat in chickens fed in two, three and four phases were similar with reduced protein diets (2%). The use of synthetic amino acids (methionine, lysine, threonine and tryptophan), in diets in each phase allows the reduction of protein percentage in 2, 3 and 4 feeding phases programs while reducing formulation costs.

 

 

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2. DARI RL, PENZ JR AM, KESSLER AM, JOST HC. Use of digestible amino acid and the concept of ideal protein in feed formulation for broilers. J Appl Poult Res 2005;14:195-203.

3. NRC. National Research Council. The Nutrient Requirements of Poultry. 9th ed. Washington DC, USA: National Academy Press, 1994.

4. CUCA GM, ÁVILA GE, PRO MA. Alimentación de las Aves. 8ª ed. Chapingo, Estado de México, México: Universidad Autónoma Chapingo, 1996.

5. DOZIER WA, GORDON RW, ANDERSON J, KIDD MT, CORZO A, BRANTON SL. Growth, meat yield, and economic responses of broilers provided threeand four-phase schedules formulated to moderate and high nutrient density during a fifty-six-day production period. J Appl Poult Sci 2006;15:312-325.

6. ROUSH WB, BOYKIN D, BRANTON SL. Optimization of phase feeding of starter, grower, and finisher diets for male broilers by mixture experimental design:Fortyeight-day production period. Poult Sci 2004;83:1264- 1275.

7. POPE T, EMMERT JL. Phase-feeding supports maximum growth performance of broiler chicks from forty-three to seventy-one days of age. Poult Sci 2001;80:345-352.

8. KERR BJ, KIDD MT. Amino acid supplementation of low-protein broiler diets: 2. Formulation on an ideal amino acid basis. J Appl Poult Sci 1999;8:310-320.

9. BAKER DH. Ideal amino acid patterns for broiler chicks. In: D´MELLO JPDF, editor. Amino Acids in Animal Nutrition. 2nd ed. Edinburgh, UK:CABI Publishing. 2003:223-236.

10. AFTAB U, ASHRAF M, JIANG Z. Low protein diets for broilers. World Poult Sci 2006;62: 688-701.

11. URDANETA R, DE LANG MK, PEÑA OL, LEESON S. Lysine requirements of young broiler chickens are affected by level of dietary protein. Can J Anim Sci 2005;85:195-205.

12. HUSSEIN AS, CANTOR AH, PESCATORE AJ. Effect of low protein diets with amino acid supplementation on broiler growth. J Appl Poult Sci 2001;10:354-362.

13. INSTITUTO NACIONAL DE ESTADÍSTICA, GEOGRAFÍA E INFORMÁTICA. Tláhuac: Cuaderno de información básica delegacional. México DF: INEGI, 1992.

14. ARBEITSGEMEINSCHAFT FW, Trade Association AWT. Amino acids in animal nutrition. Bergen, Germany: Agri-Media GmdH, 2000.

15. MARISCAL LG, ÁVILA GE, TEJADA I, CUARÓN JA, VÁSQUEZ PC. Contenido de aminoácidos totales y digestibles verdaderos para aves y cerdos de los principales ingredientes utilizados en Latinoamérica. México DF: Instituto Nacional de Investigaciones Forestales y Agropecuarias, 1995.

16. AOAC. Official Methods of Analysis. 17th ed. Washington, DC, USA: Association of Official Analytical Chemists, 2002

17. SPSS Inc. SPSS for Windows, version 17, 2009.

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19. BOUVAREL I, BARRIER GB, LARROUDE P, BOUTTEN B, LETERRIER SC, MERLET F et al. Sequential feeding programs for broiler chickens: Twenty-four- and forty-eight-hour cycles. Poult Sci 2004;83:49-60.

20. TERRAZAS FMM, ÁVILA GE, CUCA GM, SORIA N. Efecto de la incorporación de harina de pescado con distinto grado de cocción a dietas para pollos de engorda formuladas a un perfil de aminoácidos digestibles. Téc Pecu Méx 2005;43:297-308.

21. DELEZIE E, MAERTRNS L, HUYGHEBAERT G, LIPPENS M. Can choice feeding improve performances and N-retention of broilers compared to a standard three-phase feeding schedule? Br Poult Sci 2009;50:573-582.

22. CORZO A, MORAN JR. ET, HOEHLER D. Lysine need of heavy broiler males applying the ideal protein concept. Poult Sci 2002;81:1863-1868.

23. GUTIERREZ ON, SURBAKTI A, HAQ JB, BAILEY CA. Effect of continuous multiphase feeding schedules on nitrogen excretion and broiler performance. J Appl Poult Sci 2008;17:463-470.

24. WIJTTEN PJA, LEMME A, LANGHOUT DJ. Effects of different dietary ideal protein levels on male and female broiler performance during different phases of life: Single phase effects, carryover effects, and interactions between phases. Poult Sci 2004;83:2005- 2015.

25. HAN Y, SUZUKI H, PARSONS CM, BAKER DH. Amino acid fortification of a low-protein corn and soybean meal diet for chicks. Poult Sci 1992;71:1168-1178.

26. VIEIRA SL, LEMME A, GOLDENBERG DB, BRUGALLI I. Responses of growing broilers to diets with increased sulfur amino acids to lysine rations at two dietary protein levels. Poult Sci 2004;83:1307-1313.