E.A. Mustafa and E.A. ElZubeir
The authors' address is: Institute of Animal Production, University of Khartoum, PO Box 32, Khartoum North, the Sudan.
SHORT COMMUNICATIONS/BRÈVES COMMUNICATIONS/COMUNICACIONES BREVES
The use of sorghum grains in industrial processing to yield starch and sugar results in by-products with great potential in poultry feeding (Hamid and ElZubeir, 1990; Khalifa and ElZubeir, 1990; ElZubeir, ElBashir and Salih, 1990). These by-products include sorghum gluten meal, sorghum germ meal and sorghum gluten feed. Although sorghum gluten feed has been fed to broiler chicks without adverse effects on their performance (ElZubeir, ElBashir and Salih, 1990), additional work is required to characterize its nutrient composition relative to soybean meal. Thus, the present study was planned to investigate the effects that replacing soybean meal with sorghum gluten feed has on broiler chick performance.
The composition of soybean meal, sorghum gluten feed and the experimental diets are shown in Tables 1 and 2. The experimental diets consisted of a control, with soybean meal as a main source of protein, and other diets in which sorghum gluten feed was included at 15, 30 and 75 percent of air-dried diet. Levels of 15 and 30 percent sorghum gluten feed will replace about 25 and 50 percent of soybean meal, respectively. If used at a level of 75 percent, sorghum gluten feed will be the main source of protein. The diets were calculated to be isonitrogenous and isoenergetic with respect to apparent metabolizable energy.
Experiment 1
Two hundred unsexed broiler chicks (Lohmann) were selected on a body weight basis from a group of chicks that had been fed on a commercial starter diet for one week. They were then randomized into 20 groups containing ten birds each. The groups were allocated to one of four treatments, each with five replicates. The birds were kept in an open-sided deep-litter poultry house, with free access to feed and water. Chicks were group-weighed at weekly intervals and feed consumption by each group was determined at the time of weighing. Mortality was recorded daily for each pen. At the end of the feeding trial (49 days), all the birds were investigated for leg abnormalities. Five birds were then selected at random from each pen and slaughtered. The liver, bursa and abdominal fat pad were removed and weighed.
1. Chemical analysis1 and amino acid composition of sorghum gluten feed and soybean meal on air-dried basis
Analyse chimique et composition en acides aminés du gluten de sorgho et du tourteau de soja après dessiccation à l'air
Análisis químico y contenido de aminoácidos del pienso de gluten de sorgo y la harina de soja (materia seca al aire)
|
Nutrients |
Sorghum gluten feed |
Soybean meal (solvent extracted) | |
|
Dry matter (g/kg) |
950 |
946 | |
|
Ether extract (g/kg) |
76 |
80 | |
|
Crude protein (g/kg) |
267 |
436 | |
|
Crude fibre (g/kg) |
61 |
64.5 | |
|
Metabolizable energy (MJ/kg) |
9.96 |
9.37 | |
|
Calcium (g/kg) |
0.29 |
2.9 | |
|
Total phosphorus (g/kg) |
1.70 |
6.5 | |
|
Sodium (g/kg) |
0.18 |
0.4 | |
|
Potassium (g/kg) |
0.61 |
20 | |
|
Iron (mg/kg) |
2 056.10 |
120 | |
|
Manganese (mg/kg) |
254.33 |
29 | |
|
Zinc (mg/kg) |
157.66 |
27 | |
|
Ash (g/kg) |
27 |
52 | |
|
Amino acids (g/100 g protein) | |||
|
|
- lysine |
0.307 |
2.93 |
|
|
- methionine |
0.484 |
0.65 |
|
|
- arginine |
0.255 |
3.28 |
|
|
- histidine |
0.860 |
1.10 |
|
|
- isoleucine |
1.099 |
2.39 |
|
|
- tannin (catechin equivalent %) |
0.002 |
- |
1 Analysed values are means of duplicate assays by methods of AOAC (1975).
2. Composition of the experimental diets
Composition des régimes alimentaires expérimentaux
Composición de las dietas experimentales
|
Ingredients |
Diet | |||
|
|
Sorghum gluten feed:soybean meal | |||
|
|
0:100 |
25:75 |
50:50 |
100:0 |
|
|
(g/kg) | |||
|
Sorghum |
527.1 |
500 |
440 |
221.4 |
|
Soybean meal |
370 |
278.9 |
204 |
- |
|
Sorghum gluten feed |
- |
150 |
300 |
750 |
|
Groundnut oil |
64.1 |
37.9 |
24.3 |
|
|
Oyster shell |
18 |
16 |
16.3 |
14 |
|
Bone meal |
14.7 |
9.8 |
6.5 |
2 |
|
Salt |
3 |
3 |
3 |
3 |
|
Vitamin-mineral pre-mix1 |
2 |
2 |
2 |
2 |
|
Lysine monobydrochloride |
- |
1.3 |
2.6 |
6.2 |
|
Methionine |
1.1 |
1.2 |
1.3 |
1.4 |
|
Calculated composition (fresh weight basis) | ||||
|
Crude protein |
230 |
226.5 |
226 |
228.4 |
|
Calcium |
11.3 |
10 |
10 |
10 |
|
Available phosphorus |
5.5 |
5 |
5 |
5 |
|
Methionine |
4.6 |
4.6 |
4.6 |
4.6 |
|
Lysine |
1.26 |
1.2 |
1.2 |
1.2 |
|
Metabolizable energy (MJ/kg) |
13.39 |
13.21 |
13.18 |
13.34 |
|
Determined composition | ||||
|
Dry matter |
948.5 |
948 |
948 |
955 |
|
Crude protein |
222 |
210 |
224 |
215 |
|
Ether extract |
89.5 |
65.7 |
74.7 |
61 |
1 Provided per kg of diet: Vitamin A, 800 IU: Vitamin D3, 1 600 IU; Vitamin E, 11 mg; riboflavin, 9 mg; pantothenic acid, 11 mg; Vitamin B12, 13 mg; niacin, 26 mg; choline, 900 mg; Vitamin K, 1.5 mg; folic acid, 1.5 mg; biotin, 0.25 mg; ethoxyquine (antioxidant), 125 mg; manganese, 55 mg; zinc, 55 mg; copper, 5 mg; iron, 30 mg; selenium, 0.1 mg.
3. Performance of chicks (at seven weeks) fed on diets containing sorghum gluten feed
Performances de poussins de 7 semaines alimentés avec des régimes contenant du gluten de sorgho
Rendimiento de los pollos (7 semanas) sometidos a dietas con pienso de gluten de sorgo
|
Item |
Sorghum gluten feed in the diet (g/kg) |
±SE |
Linear effects (F values for significance) | |||
|
|
0 |
150 |
300 |
750 |
|
|
|
Weight gain (g/chick)1 |
1 946.2a |
1 925.2a |
1 679.4b |
436.9c |
1.41 |
-15.24*** |
|
Feed intake (g/chick)1 |
3650.6a |
3 820.6b |
3 700.9a |
2333.8c |
2.49 |
-7.8*** |
|
Feed conversion ratio (g/g live weight gain)1 |
1.79a |
1.91a |
2.14a |
4.32b |
0.00046 |
10.80*** |
|
Liver relative weight² |
1.59a |
1.61a |
1.61a |
2.85b |
0.00026 |
6.94*** |
|
Bursa relative weight² |
0.27a |
0.27a |
0.25a |
0.10b |
0.00040 |
-6.37*** |
|
Abdominal fat relative weight² |
2.15a |
2.84b |
2.17a |
0,47c |
0.003 |
-10.89*** |
|
Tibia ash (%)² |
48.04a |
44.39a |
44.90a |
46,77a |
0.063 |
-0.012 NS |
|
Chicks with leg abnormalities |
0/50 |
0/50 |
0/50 |
0/50 |
- |
- |
|
Normality (%) |
0 |
2 |
0 |
2 |
- |
- |
1 Average of 50 chicks per treatment ± standard error of mean (SE).
² Average of 52 chicks per treatment ± standard error of mean (SE).
a,b,c Means in the same row with different superscripts are significantly different (p<0.05).
*** p<0.01.
NS = no significant difference (p>0.05).
4. Protein utilization of the diet as affected by sorghum gluten feed
Effets du gluten de sorgho sur l'utilisation des protéines du régime alimentaire
Influencia del pienso de gluten de sorgo sobre la utilización de las proteínas de la dicta
|
Item |
Sorghum gluten feed in the diet (% air-dried) |
±SE |
Linear effects (F values for significance) | |||
|
|
0 |
15 |
30 |
750 |
|
|
|
Nitrogen intake (g/bird/day) |
532a |
5.02a |
4.32b |
3.51c |
0.002 |
-7.96 |
|
Excreted (g/bird/day) |
2.01a |
2.73b |
2.63c |
1.74d |
0.002 |
-2.23 NS |
|
Absorbed (g/bird/day) |
3.31a |
2.29b |
1,70c |
1.77c |
0.002 |
-9.07*** |
|
Weight gain (g/bird) |
1 986.80a |
1 968.50a |
1 557.30b |
582.50c |
1.284 |
-16.12*** |
Note: Average of five e chicks per treatment ± standard error of mean (SE).
a,b,c,d Means in the same row with different superscripts are significantly different (p<0.05).
*** p<0.001.
NS = no significant difference (p>0.05).
Experiment 2
Twenty-two-week-old, individually caged birds (five birds/diet) from the batch used in Experiment 1 were used to determine nitrogen retention by the total collection method. They were given the experimental diets (Table 2) for six weeks, followed by a collection period of three days.
Chemical analysis
Excreta and feed samples were analysed by standard methods (AOAC, 1975).
Statistical analysis
Data were subjected to an analysis of variance and regression as described by Steel and Torrie (1960).
Results
Replacement of soybean meal (SBM) with sorghum gluten feed (SGF) in broiler chicks' diets caused a significant linear reduction (p<0.001) in weight gain and feed intake and increased (p<0.001) the feed/gain ratio throughout the experimental period (Table 3). The reduction in weight gain and feed intake was most evident at the highest level of SGF inclusion in the diet. Substitution of SGF with SBM increased (p<0.001) liver relative weight, whereas bursa and abdominal fat relative weight was decreased (p<0.001). Tibia ash and the incidence of leg abnormalities were not significantly affected by dietary treatment. Nitrogen intake and absorption (g/bird/day) decreased (p<0.001) with the increasing level of SGF (Table 4). Mortality during the study was considered to be within the normal range and appeared to occur at random with no indication of response to dietary treatment.
Discussion
The results of two experiments incorporating SGF in the diet in replacement for SBM demonstrated that SGF was not equivalent to SBM as a main source of protein for broiler chicks. However, SGF can substitute about 25 percent of SBM with no detrimental effect on broiler chick performance. This equates to about 15 percent of SGF in the diet, which is less than that reported in a previous study (ElZubeir, ElBashir and Salih, 1990). The difference is presumably the result of the fact that SGF in the present study was not combined with other protein sources. The reduction in weight gain associated with feeding high levels of SGF was paralleled by a reduction in feed consumption, which complicates the interpretation of the results. The weight gain of chicks given the highest level of SGF is seriously retarded to an extent greater than that which could be expected from lowered feed intake. The reduction in bursa relative weight in chicks given the 75 percent SGF-based diet is an indication that this diet acted as a stress factor; bursa weight has been reported to regress in response to hormones produced during stress (Siegel and Beane, 1961; Zarrow, Greeman and Peter, 1961).
The prices of poultry feed ingredients in the Sudan, and probably in other countries as well, justify the search for cheaper ingredients. In addition to availability of SGF, a unit weight of SBM costs four times as much as that of SGF. Consequently, the growth depression and deterioration in feed conversion ratio caused by a replacement of SBM with up to 50 percent of SGF could be accepted on an economic basis. +
Bibliography
AOAC. 1975. Official Methods of Analysis. W. Homwitz, ed. Washington, DC, Association of Official Analytical Chemists.
ElZubeir, E.A., ElBashir, T.E. & Salih, A.M. 1990. Sorghum gluten feed in poultry diets: effect on broiler performance and sensory evaluation of carcasses. Sci. Food Agric., 52: 215-219.
Hamid, I.I. & ElZubeir, E.A. 1990. Effect of feeding graded levels of sorghum gluten meal (SGM) on the performance of broiler chicks. Anim. Feed Sci. Technol., 29: 289-294.
Khalifa, N.A. & ElZubeir, E.A. 1990. Effect of sorghum gluten feed on the performance of hens and on egg quality. Sci. Food Agric., 53: 415-417.
Siegel, H.S. & Beane, W.L. 1961. Time response of single intramuscular dose of ACTH in chickens. Poult. Sci., 40: 216-219.
Steel, R.G. & Torrie, J.H. 1960. Principles and Procedures of Statistics. New York, McGraw-Hill.
Zarrow, M.X., Greeman, D.L. & Peter, L.E. 1961. Inhibition of the bursa of Fabbricius and Stilbestrol-stimulated oviduct of the chick. Poult. Sci., 40: 87.
