J APPL POULT RES 2008. 17:463-470. doi:10.3382/japr.2008-00015
© 2008 Poultry Science Association
Effect of Continuous Multiphase Feeding Schedules on Nitrogen Excretion and Broiler Performance
O. Gutierrez1,
N. Surbakti,
A. Haq,
J. B. Carey and
C. A. Bailey
Department of Poultry Science, Texas A&M University, College Station 77843-2472
1 Corresponding author: ogutierrez{at}tamu.edu
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SUMMARY
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Two experiments were conducted simultaneously to evaluate the effects of continuous multiphase feeding programs on nitrogen excretion and broiler performance. Birds in both experiments were fed diets based on 1 of 3 unique feeding schedules. One feeding program consisted of an industry-type 4-phase schedule, whereas the remaining treatments consisted of diets that were blended and replaced every 3 d. One of these continuous multiphase feeding programs was based on industry average nutrient compositions, whereas the other feeding program was based on the EFG Broiler Growth Model. In experiment 1, 60 one-day-old male broiler chicks were randomly placed in 30 separate battery brooding pens with 3 unique feeding schedules (10 replicates per treatment). Nitrogen analyses were conducted on broiler excreta and ground, whole birds. Experiment 2 was conducted to evaluate the effects of continuous multiphase feeding programs on broiler performance in floor pens. A total of 540 one-day-old male broiler chicks were placed in 36 pens, yielding 12 replicates of 3 treatments. Continuous multiphase feeding schedules improved BW gain and the feed-to-gain ratio during wk 3 and 4 (experiment 1) and wk 5 and 6 (experiment 2). Nitrogen excretion and retention, however, were unaffected by the different feeding programs.
Key Words: continuous multiphase feeding • broiler • performance • nitrogen
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DESCRIPTION OF PROBLEM
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Nutrient emission can be defined as the difference between the amount of a given mineral that is fed to an animal and the amount that is retained within the tissues of that animal. With a nitrogen efficiency rate of 34%, almost two-thirds of the dietary nitrogen that chickens consume must be excreted and disposed of [1]. Until recently, consideration of the response of an animal to its nutrient supply was confined to maximizing the efficiency of food-product outputs, with less attention being paid to the volume of mineral emissions contained in animal waste. According to Morse [2], the excretion of nitrogen originating from dietary protein is the most prevalent form of nitrogen pollution resulting from animal production. Several approaches to limiting nitrogen excretion in monogastric animals have been proposed. These include strategies such as the implementation of dry manure or litter storage and environmental control to limit moisture accumulation and subsequent nitrogen volatilization. Additionally, nutritional strategies that include the use of specific synthetic amino acids, and the implementation of multiphase feeding schedules to meet the age-based nutritional requirements of an animal more precisely have been suggested [3].
One nutritional approach to reducing nutrient excretion is to feed diets formulated to meet the exact requirements of birds on any given day. Unfortunately, accuracy in knowing an animal’s specific nutrient requirements on any given day is difficult because nutritional requirements are moving targets influenced by many factors, such as the environment in which the animal is grown, the presence of a disease challenge, and changes in the genetic characteristics of the animal in question.
Most commercial broiler grow-out programs in the United States use a 4-phase feeding program using starter, grower, finisher, and withdrawal diets [4]. In an attempt to accommodate the expected needs associated with additional growth under field conditions, the commercial broiler industry typically uses greater dietary levels for certain nutrients, such as essential amino acids [4]. Because protein or amino acid requirements change continuously as age increases, a single diet fed over a moderate to long period of time either under- or oversupplies broilers with specific amino acids relative to the requirements of that animal.
According to Belyavin [5], one approach to overcoming this problem is to feed more diets throughout the growing period. A strategy that matches feed composition to the broilers’ nutritional requirements during progressive periods of growth is called phase feeding or multiphase feeding. Multiphase feeding programs are designed to meet the nutritional needs of birds more closely at specific points in their life cycle (Figure 1
). Ideally, an increase in the number of feeding phases would result in more accurate nutrient composition as it relates to the birds’ nutrient requirements, although from a management perspective, the delivery of more than 4 or 5 diets per flock would not be practical. However, with an on-farm feed-mixing system that uses 2 premixed diets, one relatively high in protein content and the other relatively low in protein content, one could theoretically mix and deliver feed based on an age-related protein requirement. Given that this feeding strategy requires the development of a model that accounts for stage of production, genetic potential, production objective, and environmental factors, one could possibly achieve reduced nutrient excretion caused by the daily reduction in feed nutrient levels while maintaining performance or production levels.
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Figure 1. Theoretical relationship of 3-phase and 5-phase feeding programs on the essential amino acid (EAA) supply relative to the EAA requirement in broilers over time (not drawn to scale).
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The objective of this study was to compare nitrogen excretion and broiler performance by using an industry-type 4-phase feeding program and 2 unique continuous multiphase feeding programs for which 2 diets were blended every 3 d over a 7-wk period. Feed costs associated with these diets were also analyzed.
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MATERIALS AND METHODS
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Experiment 1
Sixty 1-d-old Ross x Ross 308 [6] male broilers were randomly placed in 30 brooder battery pens (2 chicks per pen). Treatments consisted of a 4-phase feeding program and 2 unique continuous multiphase feeding programs in which the diets were mixed and replaced every 3 d over a 49-d growing period. The 4-phase feeding program served as the control treatment and consisted of starter (0 to 3 wk); grower (3 to 5 wk); finisher (5 to 6 wk); and withdrawal (6 to 7 wk) diets. Nutrient compositions (Table 1) were based on commercial industry averages [4]. One of the continuous multiphase feeding programs used in this study was based on industry average nutrient compositions such that nutrient content would match the control group at the approximate midpoint of a given feeding phase (Table 2). The other continuous multiphase feeding program was based on the EFG Broiler Growth Model [7]. This model suggests comparatively greater protein levels during the early stages of broiler development (Table 3). Diets were linearly blended every 3 d by using changing fractions of either a combination of diets A and B, diet B, a combination of diets B and C, or diet C to create 16 nutritionally distinct feeds for both the industry-based and EFG continuous multiphase treatments [i.e., feed 1 (d 1 to d 3) = 87.5% diet A, 12.5% diet B; feed 2 (d 4 to d 6) = 75% diet A, 25% diet B; etc.]. There were 10 replicates per treatment, and all diets were provided ad libitum in mash form. Water was freely available throughout the study and light was provided continuously.
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Table 2. Composition of the basal diets from which the industry-based continuous multiphase diets were blended every 3 d
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Table 3. Composition of the basal diets from which the EFG1-based continuous multiphase diets were blended every 3 d
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Nitrogen Analysis.
A metal tray was placed under each pen, and excreta were collected and weighed daily at approximately 1030 h. Unconsumed feed was weighed, discarded, and replaced with fresh feed daily. Body weight, by pen, was assessed daily. Ambient temperature was reduced from 28 to 20°C over the course of the experiment. All excreta samples were frozen at –4°C until they could be analyzed for nitrogen and DM. Body composition data were obtained from a total of 30 birds (10 per treatment) that had been randomly selected and identified by wing-banding at d 1. They were killed by asphyxiation and immediately frozen at –4°C. After thawing, frozen birds were steamed for 70 min, allowed to cool for 4 h, and minced into small pieces. These pieces were then ground 3 times with a Hobart mixer fitted with a grinding attachment [8]. For the first grinding, a 0.95-cm die was used, whereas for the second and third grindings, a 0.32-cm die was used. Nitrogen analyses of broiler excreta and ground, whole bird were performed with a Leco combustion nitrogen analyzer [9].
Experiment 2
The purpose of this study was to assess the floor pen performance of broilers consuming diets identical to those in experiment 1. A total of 540 one-day-old Ross x Ross 308 [6] male broilers were randomly placed in 36 floor pens (1.8 x 2.0 m) on fresh pine shavings. Body weights, by pen, were assessed weekly. All diets were fed ad libitum and any remaining feed was weighed, discarded, and replaced every 3 d. Feed and water were freely available throughout the study and light was provided continuously. Data were not collected for nitrogen retention or excretion.
Statistical Analysis
All parameters were analyzed by 1-way ANOVA within a randomized complete block design, using feeding program as a fixed factor [10]. When significant main effects were detected, differences among treatment means were established by using the Duncan multiple range test procedure. Statements of significance were based on P < 0.05.
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RESULTS AND DISCUSSION
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Experiment 1
There was no significant effect of feeding schedule on cumulative BW gain in wk 1 and 2 (Table 4). This finding was consistent with the results of Warren and Emmert [11], who reported that multiphase feeding had no significant effect during this early period because of relatively low rates of feed consumption. However, during wk 3 and 4, birds on both continuous multiphase feeding programs had significantly greater cumulative BW gain and improved FCR relative to birds on the 4-phase feeding program. Week 3 represented a period of overfeeding for the industry-type 4-phase feeding program, whereas wk 4 represented a period of underfeeding as the starter diet was switched to the grower diet. By wk 5, and continuing through the remainder of the trial, no significant differences were noted among feeding programs. Moran [12] reported similar compensatory growth in male broilers consuming diets differing in CP levels between wk 2 and 5, with significant differences in BW correlating to greater protein levels at wk 5 but disappearing by 7 wk of age.
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Table 4. Cumulative weight gain, feed consumption, and feed conversion rate of broilers fed by various multiphase feeding schedules and reared in brooder batteries1
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There was no significant effect of continuous multiphase feeding on cumulative feed consumption from wk 1 to 7 (Table 4
). Other researchers have also failed to note significant differences in feed consumption of broilers fed multiphase diets [11, 13, 14]. Continuous multiphase feeding had no effect on the cumulative feed-to-gain ratio from wk 1 to 2, but there was a significant effect by wk 3 and 4 relative to those receiving the 4-phase feeding program (Table 4). No significant differences in feed-to-gain ratio were detected after wk 4 of the study.
There was no treatment effect on whole-body nitrogen content, which averaged 8.50, 8.58, and 8.27% (DM basis) for the industry 4-phase, industry continuous multiphase, and EFG continuous multiphase feeding programs, respectively (data not shown). Average daily nitrogen intake was greater for both continuous multiphase treatments compared with the control treatment during the first 12 d of the study, but no associated differences in excretion or retention were observed (Table 5). No differences in nitrogen intake, retention, or excretion were observed after d 12.
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Table 5. Average daily nitrogen intake, excretion, and retention of broilers fed according to various multiphase feeding schedules1
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Bregendahl et al. [15] compared nitrogen retention versus excretion in broilers fed diets with 19 and 20% CP and found nitrogen excretion to be directly correlated with intake. However, no differences in cumulative nitrogen intake, excretion, or retention were observed in the present study. Approximately 17% of nitrogen intake for all 3 treatments was unaccounted for and was presumably lost to the atmosphere as ammonia (data not shown).
Experiment 2
Cumulative weight gains were significantly greater for both continuous multiphase feeding programs relative to the 4-phase feeding program at wk 5 and 6 (Table 6). By wk 7, however, no significant differences were observed. Feed intake and cumulative BW gain in this experiment were lower than during experiment 1. This is most likely an effect of ambient temperature, because experiment 2 was conducted in an open-sided barn during the summer, whereas in experiment 1, birds were maintained in an air-conditioned room where the temperature could be adjusted appropriately. Significant differences in FCR were observed during wk 5 and 6 (Table 6). Because significant differences in feed consumption were not observed, differences in feed-to-gain ratio appeared to be due primarily to differences in BW gain.
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Table 6. Cumulative weight gain, feed consumption, and feed conversion rate of broilers fed according to various multiphase feeding schedules and reared in floor pens1
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Feed cost per kilogram of BW gain for both continuous multiphase feeding programs was lower compared with the 4-phase feeding program (Table 7). This finding is consistent with that of Pope and Emmert [13], who reported that multiphase feeding reduced feed costs during the grower and finisher periods. Overall mortality rate in both experiments was very low (<3%), and no significant differences were observed among treatment groups throughout the study period (data not shown).
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Table 7. Effect of various multiphase feeding schedules on feed costs per kilogram of gain in experiments 1 and 2 ($US)1
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CONCLUSIONS AND APPLICATIONS
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- Continuous multiphase feeding programs did not have an effect on nitrogen retention or excretion rates in this study.
- No effect on 7-wk cumulative BW gain or FCR was attributable to the continuous multiphase feeding programs, although intermediate effects on both of these parameters were observed at wk 3 and 4 (experiment 1) and wk 5 and 6 (experiment 2).
- The intensive multiphase feeding program could potentially lower feed costs per kilogram of BW gain. However, the feasibility of continuous multiphase feeding depends on the cost associated with feed mixing and the capital equipment cost of an on-site blending system, neither of which was addressed in these experiments and would presumably be quite high.
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REFERENCES AND NOTES
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- Van der Hoek, K. W. 1998. Nitrogen efficiency in global animal production. Environ. Pollut. 102(Suppl. 1):127–132.[CrossRef]
- Morse, D. 1995. Environmental considerations of livestock producers. J. Anim. Sci. 73:2733–2740.[Abstract]
- Ferket, P. R., E. van Heuten, T. A. van Kempen, and R. Angel. 2002. Nutritional strategies to reduce environmental emissions from nonruminants. J. Anim. Sci. 80(Suppl. 2):E168–E182.[Abstract/Free Full Text]
- Agri Stats Inc. 2001. Annual Live Production. Agri Stats Inc., Fort Wayne, IN.
- Belyavin, C. G. 1999. Nutrition management of broiler programmes. Pages 93–105 in Recent Advances in Animal Nutrition. Nottingham University Press, Leicestershire, UK.
- Aviagen Inc., Huntsville, AL.
- EFG Broiler Growth Model, EFG Software, Natal, South Africa.
- Mixer, Hobart Co., Troy, OH.
- Model FP-428, Leco Corp., St. Joseph, MI.
- SAS Institute. 2000. SAS User’s Guide: Statistics. Version 6.12 ed. SAS Inst. Inc., Cary, NC.
- Warren, W. A., and J. L. Emmert. 2000. Efficacy of phase-feeding in supporting growth performance of broiler chicks during the starter and finisher phases. Poult. Sci. 79:764–770.[Abstract/Free Full Text]
- Moran, E. T. Jr. 1979. Carcass quality changes with the broiler chickens after dietary protein restriction during the growing phase and finishing period compensatory growth. Poult. Sci. 58:1257–1270.[Web of Science]
- Pope, T., and J. L. Emmert. 2001. Phase-feeding supports maximum growth performance of broiler chicks from forty-three to seventy-one days of age. Poult. Sci. 80:345–352.[Abstract/Free Full Text]
- Pope, T., L. N. Loupe, J. A. Townsend, and J. L. Emmert. 2002. Growth performance of broilers using a phase-feeding approach with diets switched every other day from forty-two to sixty-three days of age. Poult. Sci. 81:466–471.[Abstract/Free Full Text]
- Bregendahl, K., J. L. Sell, and D. R. Zimmerman. 2002. Effect of low-protein diets on growth performance and body composition of broiler chicks. Poult. Sci. 81:1156–1167.[Abstract/Free Full Text]
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SUMMARY
DESCRIPTION OF PROBLEM
