J APPL POULT RES 2006. 15:574-578
© 2006 Poultry Science Association
Feeding of Unground Pearl Millet to Laying Hens
A. R. Garcia and
N. M. Dale1
Department of Poultry Science, University of Georgia, Athens 30602
Correspondence: 1 Corresponding author: ndale{at}uga.edu
 |
SUMMARY
|
|---|
The use of new varieties of pearl millet (PM) as an alternative feed ingredient for poultry has gained increased interest due to the favorable nutritional characteristics of this grain. However, its incorporation into poultry feeds has been limited because commercial availability of PM in the United States is currently low and also because many feed mills lack the capacity to store more than 1 ground grain. Previous studies have demonstrated the advantages of the inclusion of moderate levels of whole grains in poultry feeds. A series of 3 experiments was conducted to investigate whether unground PM would be a satisfactory feed ingredient for laying hens. In Experiment 1, diets containing 5, 10, 20, 30, and 40% unground PM were fed. At the end of a 7-d feeding period, it was determined that the percentage of whole seed disappearance was equal to or greater than 98% at all levels of inclusion. No significant differences in whole seed disappearance were detected among treatments, indicating that laying hens have the capacity to break down whole PM seeds. In Experiment 2, diets containing 0 or 15% inclusion of either ground or unground PM were fed to laying hens for a 7-d feeding period. Starch digestibility of the diets was determined to be >97% for all treatments. Significantly greater starch digestibility was observed in the hens fed the 15% unground PM as compared with the hens receiving the ground PM diet. In Experiment 3, after a 4-wk feeding period, it was determined that the inclusion of 10% unground PM does not have a negative or positive effect on feed consumption or egg production. These results indicate that PM is a satisfactory feed ingredient for laying hens that can be included in the unground form at moderate levels.
Key Words: pearl millet • unground grain • laying hen
|
DESCRIPTION OF PROBLEM
|
|---|
Pearl millet (PM) is grown in the semiarid, low-input dry-land agricultural regions of Africa and southeast Asia, because it is adapted to soils of low fertility and moisture content [1]. These characteristics make PM a possible alternative crop in the southeastern United States, where cultivation of crops is inadequate to meet needs, and shipping corn from other states increases feed cost [2]. The inclusion of PM to poultry diets has gained interest due to the favorable nutritional characteristics of this grain. The ME content is comparable to that of corn [3]. Furthermore, PM has higher CP (12 to 14%) and Lys (0.38 to 0.41%) concentrations than either corn or sorghum [4, 5, 6]. Previous studies conducted with PM in broiler chickens have yielded similar and sometimes improved results to those of birds fed corn-based feeds in terms of growth performance and carcass characteristics [3, 7].
The incorporation of whole grains into poultry feeds has become a more common practice, especially in European countries, as a way of reducing feed cost due to handling and processing. Moreover, this practice has resulted in some beneficial effects associated with increased gizzard activity, such as improvement in feed conversion ratio [8], increased starch digestibility [9] and greater apparent ME [10].
Currently, little PM is grown in the United States. Because PM is a small-sized grain (2 to 3 mm in diameter) and given the fact that commercial availability of PM is still low, the incorporation of moderate levels of PM into poultry feeds seems feasible. In practice, a major impediment to the use of alternative grains is that many feed mills lack the storage capacity for more than 1 ground grain. However, in previous research conducted with broilers, it was shown that moderate levels of inclusion of whole PM can be incorporated into the feed without detrimentally affecting growth performance or carcass traits [11]. In addition, the beneficial effects of feeding whole grains to poultry at moderate inclusion levels have been well documented [8, 9, 10]. Thus, unground PM might be of interest to the laying hen industry, which represents a smaller market for grains than the broiler industry, provided that whole PM is a satisfactory feed ingredient. Therefore, the objective of the present research was to determine if unground PM could be well utilized by laying hens.
|
MATERIALS AND METHODS
|
|---|
To evaluate the incorporation of unground PM into laying hen diets, 3 experiments were conducted. In all studies, 50- to 56-wk-old, Hy-line W36 strain [12], Single Comb White Leghorn laying hens were used. Hens were individually caged in 10 x 16 in. wire cages.
Experiment 1
The objective of this experiment was to evaluate whole seed disappearance in laying hens receiving different levels of inclusion of unground PM (TifGrain 102). This test was performed as an indicator of the ability of the bird to break down whole seeds [10]. Forty 50-wk-old hens were randomly assigned to 5 dietary treatments, consisting of the incorporation of 5, 10, 20, 30, and 40% unground PM to corn-soybean meal-based diets. Nutrient levels were formulated to meet NRC [13] recommendations (Table 1
). Each dietary treatment had 4 replications of 2 birds each. Feed intake and egg production were monitored daily. At 6 d of consumption of the experimental diets, the total amount of excreta produced in a 24-h period was weighed, and a measured sample (60 g) was examined for determination of whole seeds [11]. Excreta samples were resuspended in water, passed through the sieve of 1.70 mm opening diameter (US sieve #12), and the number of whole seeds retained in the sieve were counted. The percentage of whole seed disappearance was calculated based on the number of whole seeds found in the excreta. This number was then divided by the number of whole seeds present in the feed consumed and multiplied by 100 to be expressed as a percentage.
Experiment 2
The objective of this experiment was to determine if the inclusion of whole PM seeds in laying hen diets might affect starch digestibility. Ninety-six 51-wk-old laying hens, in active egg production, were randomly assigned to 3 dietary treatments, consisting of 0 or 15% inclusion of either ground or unground PM (Table 1
). The level of PM used for this experiment was chosen as a more likely inclusion rate under commercial settings considering the current production of the grain. Nutrient levels met the NRC [13] recommendations. Treatments had 8 replications of 4 hens each. Celite [14] was added to the diets as an indigestible marker at 2% inclusion. Diets were fed during a 7-d feeding period. On d 7, excreta samples were collected every 30 min and immediately frozen at –20°C to prevent bacterial degradation of the starch. Excreta samples were freeze-dried, ground, and submitted to a commercial laboratory [15] for analysis of starch. Additionally, acid insoluble ash (AIA) was analyzed in both feed and excreta samples, as previously described [16]. Starch digestibility was calculated with the following formula
where Nf = percentage of starch in the feed; Ni = percentage of starch in the excreta; AIAf = percentage of AIA in the feed; AIAi = percentage of AIA in the excreta.
Experiment 3
The objective of this experiment was to determine if the inclusion of whole PM seeds might affect feed intake in laying hens. Ninety-six 52-wk-old laying hens in active egg production were randomly assigned to 2 dietary treatments, consisting of 10% inclusion of either ground or unground PM added to corn-soybean meal-based diets. Again, this level of inclusion was selected, because it would be more likely to be used commercially. The diet composition was similar to those used in Experiment 1. The diets were fed for a 4-wk feeding period. Feed intake and egg production were recorded daily throughout the experiment.
Statistical Analysis
Data from each experiment were analyzed by ANOVA. When significant differences were found (P < 0.05), treatment means were compared by using Tukey’s multiple comparison procedure [17].
|
RESULTS AND DISCUSSION
|
|---|
Results of Experiment 1 are shown in Table 2. Because the main objective of this experiment was to determine the effect of feeding unground PM on the disappearance of whole seeds in the gastrointestinal tract, the experimental period was of a 7-d duration. Thus, feed intake and egg production were not considered as principal parameters but rather to ascertain that hens remained in active egg production during the experimental period. Whole seed disappearance was 
98% for all levels of inclusion of unground PM, and no significant differences were detected among treatments. These results indicate that laying hens are capable of digesting whole PM seeds when present in the feed in levels as high as 40%. Similar results were reported in broiler chickens [11], in which whole PM seed disappearance ranged from 95 to 98% in 14-d-old birds.
View this table:
[in this window]
[in a new window]
|
Table 2. Feed intake, egg production, and percentage of whole seed disappearance in laying hens fed different levels of inclusion of unground pearl millet (PM), Experiment 1
|
|
Results of starch digestibility are shown in Table 3. For the 3 treatments, starch digestibility of the diets was >97%, as determined by balance. No statistically significant differences were detected in starch digestibility between 0% PM and 15% unground PM. However, starch digestibility of the diet containing 15% ground PM was significantly lower than the diet containing the unground form of PM. This observation is in agreement with previous studies in which starch digestibility was significantly increased in broilers fed diets containing whole wheat and barley [8, 9, 10]. The reason why starch digestibility was lower in the birds fed the ground PM as compared with the unground PM or corn is unknown. However, one of the factors affecting starch digestibility in grains is enzyme accessibility to starch granules [18], which is variable among cereal grains. Grinding cereal grains does not always result in nutritional improvement [19]. Rather, whole grains are believed to enhance gizzard function, which in turn may improve enzyme access to substrate particles. Regarding PM, no further studies have been conducted to investigate starch digestibility of this grain. Therefore, no current information is available to confirm this hypothesis. The difference in starch digestibility between ground and unground PM was <1%, indicating that there is no detrimental effect of unground PM on starch digestibility.
View this table:
[in this window]
[in a new window]
|
Table 3. Percentage of starch digestibility in laying hens fed diets containing corn or 15% inclusion of either whole or ground pearl millet (PM), Experiment 2
|
|
Results of feed intake and egg production from Experiment 3 are presented in Table 4. No significant differences were observed among dietary treatments throughout the experiment. Although the number of hens per treatment did not permit a meaningful comparison of egg production, results failed to suggest any detrimental effect of incorporating unground PM in laying hen feeds. These results indicate that laying hens can utilize whole PM when used at moderate levels of inclusion without apparent effect on feed intake or egg production. This should enable laying hen producers to use PM as an alternative grain as a strategy to reduce feed cost.
View this table:
[in this window]
[in a new window]
|
Table 4. Feed intake and egg production of laying hens fed diets with 10% inclusion of either unground pearl millet (UPM) or ground pearl millet (GPM), Experiment 3
|
|
|
CONCLUSIONS AND APPLICATIONS
|
|---|
- When incorporated into laying hen diets from 5 to 40% inclusion, over 98% of unground PM seeds were broken down in the laying hen’s digestive tract.
- Incorporation of 10% unground PM into laying hen rations does not detrimentally affect feed intake or egg production.
- Unground PM is a satisfactory feed ingredient for laying hens. The use of this grain in the unground form should be potentially favorable for egg producers as a strategy to reduce feed cost.
|
REFERENCES AND NOTES
|
|---|
- Baltensperger, D. 2002. Progress with proso, pearl and other millets. Pages 100–103 in Trends in New Crops and New Uses. J. Janick and A. Whipkey, ed. ASHS Press, Alexandria, VA.
- Durham, S. 2003. New strain of pearl millet. Agric. Res. Mag. 51:19.
- Davis, A. J., N. M. Dale, and F. J. Ferreira. 2003. Pearl millet as an alternative feed ingredient in broiler diets. J. Appl. Poult. Res. 12:137–144.[Abstract/Free Full Text]
- Ejeta, G., M. M. Hassen, and E. T. Mertz. 1987. In vitro digestibility and amino acid composition of pearl millet (Pennisetum typhoides) and other cereals. Proc. Natl. Acad. Sci. USA 84:6016–6019.[Abstract/Free Full Text]
- Adeola, O., and J. C. Rogler. 1994. Pearl millet in diets of White Pekin ducks. Poult. Sci. 73:425–435.[ISI][Medline]
- Singh, D. 2004. Subject: Evaluation of new millet varieties as a poultry feed ingredient. http://www.rirdc.gov.au/reports/CME/04-173.pdf Accessed Dec. 2004.
- Garcia, A. R., A. B. Batal, and N. M. Dale, personal communication.
- Plavnik, I., B. Macovsky, and D. Sklan. 2002. Effect of feeding whole wheat on performance of broiler chickens. Anim. Feed Sci. Technol. 96:229–236.
- Hetland, H., B. Svihus, and V. Olaisen. 2002. Effect of feeding whole cereals on performance, starch digestibility and duodenal particle size distribution in broiler chickens. Br. Poult. Sci. 43:416–423.[ISI][Medline]
- Svihus, B., E. Juvik, H. Hetland, and A. Krogdahl. 2004. Causes for improvement in nutritive value of broiler chicken diets with whole wheat instead of ground wheat. Br. Poult. Sci. 45:55–60.[ISI][Medline]
- Hidalgo, M. A., A. J. Davis, N. M. Dale, and W. A. Dozier III. 2004. Use of whole pearl millet in broiler diets. J. Appl. Poult. Res. 13:229–234.[Abstract/Free Full Text]
- Hy-Line Int., West Des Moines, IA.
- National Research Council. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC.
- Celite Corp., Lompoc, CA.
- Minnesota Valley Testing Laboratories Inc., New Ulm, MN.
- Scott, T. A., and F. Boldaji. 1997. Comparison of inert markers (chromic oxide or insoluble ash (Celite) for determining apparent metabolizable energy of wheat- or barley-based broiler diets with or without enzymes. Poult. Sci. 76:594–598.[Abstract/Free Full Text]
- SAS Institute. 1990. SAS/STAT User’s Guide. Release 6.08. SAS Inst. Inc., Cary, NC.
- Tester, R. F., J. Karkalas, and X. Qi. 2004. Starch structure and digestibility: Enzyme-substrate relationship. World’s Poult. Sci. J. 60:186–195.
- Carré, B. 2004. Causes for variation in digestibility of starch among feedstuffs. World’s Poult. Sci. J. 60:76–89.
TOP
SUMMARY
DESCRIPTION OF PROBLEM
