| Livestock Research for Rural Development 26 (4) 2014 | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
An eight week feeding trial was conducted to determine the effect of supplementation of two levels of methionine (0.2% and 0.4%) in cassava peel-based diets on the utilization of this by-product of cassava processing industry by broilers. Three hundred and twenty (320) day-old Anak strain of broiler chicks were divided into eight groups of forty birds each and the groups allotted randomly to eight diets that contained 0, 10, 15 and 20 percent Cassava Peel Meal (CPM) with either 0.2% methionine {Low Methionine Supplementation ( LMS) } or 0.4% methionine {High Methionine Supplementation (HMS)} in a factorial designed experiment. Each treatment was replicated four times and data analyzed by two way analysis of variance using General Linear Model procedure of SAS.
The average daily weight gains were similar with up to 15% CPM in the diet but were reduced with 20% CPM. Supplementation with 0.4% methionine improved daily weight gain at the 20% CPM inclusion. Feed conversion and nutrient utilization were poor at 20% CPM inclusion but were improved by 0.4% methionine. Lower abdominal fat was observed at 20% CPM inclusion compared with lower levels.
It was concluded that up to 15% CPM can be included in broiler diets using 0.2% methionine but the use of 20% CPM requires supplementation with 0.4% methionine.
Key words: carcass characteristics, feed conversion, feed intake, nutrient utilization, weight gain
The use of agro-industrial by-products for animal feeding has long been recognized as a practical way of reducing feed cost. Cassava peel is one of such promising byproducts in Nigeria and indeed most tropical countries of Africa. Cassava peel is gaining wider acceptance as feed for livestock animal (Onyeonagu and Njoku 2010) both for the ruminant and non-ruminant animals. However, the use of cassava peel like other agro-industrial by product is usually limited by anti-nutritional factors, high fibre content (Udedibie et al 2004) and processing cost that often accompany it (Iyayi et al 2004). The concentration of cyanide is higher in the peel of cassava than in the pulp with the value average about 650ppm for bitter variety and 200ppm for sweet variety (Tewe 1992). The limitation imposed on the use of cassava peel by poultry is usually manifested in form of retarded growth rate, high feed consumption, poor feed conversion and low egg production (Osei and Twumasi 1989; Osei et al 1990).
Several methods have been used to ameliorate the effects of hydrocyanic acid in cassava products on man and animals that consume them. These include processing methods like sun-drying, fermentation, cooking, addition of palm oil and feeding of high protein supplements and/or amino acids like lysine and methionine. Cyanide is detoxified to thiocyanate by the enzyme rhodanase making use of methionine as the sulphur donor (Organisation for the Prohibition of Chemical Weapons 2013) which makes this amino acid a limiting factor in cassava based-feeds. Since methionine is known to be involved in cassava detoxification, the use of this amino acid has long been suggested (Oke 1978). This hypothesis is supported by Du Thanh Hang et al (2009) who reported an improvement in the production performance of pigs when diets that contained 20% fresh cassava leaves (DM basis) were supplemented with 0.2% of synthetic DL methionine. The use of high levels of methionine may be a way of improving the utilization of cassava peel by broiler chicken. The present study was therefore conducted to evaluate the effects of two levels of methionine supplementation on the utilization of cassava peel meal-based diets by broiler chicken.
The study was conducted at the poultry brooding unit of the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso, Oyo State , Nigeria. The study site lies between latitudes 8007’N and 8012’N and longitudes 4004’E and 4015’E. The mean annual rainfall is 1247mm with relative humidity of between 75 and 95%. The location is situated at about 500m above the sea level with a mean annual temperature of 26.20C.
The cassava peel used in this study was collected from ‘Garri’ Processing Unit of the Teaching and Research Farm, Ladoke Akintola University of Technology. The peel was generated from sweet variety of cassava (TMS30572). It was rinsed in cold water and then sun-dried until the moisture content was about 12 percent. The dried product was milled to obtain what was referred to as Cassava Peel Meal (CPM). The methionine used for the study was purchased from a feed miller in Ogbomoso.
Eight diets were formulated for broilers at both starter and finisher phases (Tables 1 and 2). Four diets were formulated to contain 0, 10, 15 and 20 percent CPM respectively with 0.2 % methionine supplementation {Low Methionine Supplementation ( LMS)} while the remaining four were formulated to contain 0, 10, 15 and 20 percent CPM respectively but with 0.4% methionine supplementation {High Methionine Supplementation (HMS)}.
Three hundred and twenty day–old Anak strain of broiler chicks were used for the study. The birds were divided into eight groups of forty birds each and each group assigned to one of the eight diets in a 2*4 factorial arrangement with 4 replications (10 birds per treatment/replicate). Birds in each replicate were housed in deep litter pens measuring 3×1m. Feeds and water were supplied ad libitum during the starter and finisher phases. Vaccination and medication were carried out according to the recommendation for the derived savanna zone of Nigeria. Starter diet was fed for the first 21 days while the finisher diet was fed for the remaining 21 days of the study.
|
Table 1: Composition of the broiler starter diet |
||||||||
|
Level of CPM in the diet (%) |
||||||||
|
Ingredient |
0 |
0 |
10 |
10 |
15 |
15 |
20 |
20 |
|
Maize |
49.0 |
49.0 |
39.0 |
39.0 |
34.0 |
34.0 |
29.0 |
29.0 |
|
Cassava peel meal |
0.00 |
0.00 |
10.0 |
10.0 |
15.0 |
15.0 |
20.0 |
20.0 |
|
Soybean meal |
29.5 |
29.5 |
27.0 |
27.0 |
27.0 |
27.0 |
26.0 |
26.0 |
|
Blood meal |
0.50 |
0.50 |
1.00 |
1.00 |
1.00 |
1.00 |
2.00 |
2.00 |
|
Fish meal |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
|
Palm kernel cake |
5.00 |
5.00 |
4.50 |
4.50 |
4.50 |
4.50 |
4.50 |
4.50 |
|
Wheat offal |
6.55 |
6.35 |
8.55 |
8.35 |
8.05 |
7.85 |
7.55 |
7.35 |
|
Palm kernel oil |
1.00 |
1.00 |
1.50 |
1.50 |
2.00 |
2.00 |
2.50 |
2.50 |
|
Oyster shell |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
|
Dicalcium phosphate |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
|
Common salt |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
|
Methionine |
0.20 |
0.40 |
0.20 |
0.40 |
0.20 |
0.40 |
0.20 |
0.40 |
|
Lysine |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
|
Vitamin/min Premix# |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
|
Total |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
| Analysis, DM basis | ||||||||
|
*Crude protein, % |
21.4 |
21.5 |
21.0 |
21.0 |
20.9 |
20.9 |
20.8 |
20.8 |
|
**ME, Kcal/g |
2.86 |
2.86 |
2.83 |
2.84 |
2.74 |
2.74 |
2.67 |
2.66 |
|
*Crude fibre, % |
3.50 |
3.50 |
4.30 |
4.30 |
4.80 |
4.80 |
5.20 |
5.20 |
|
*Methionine, % |
0.48 |
0.68 |
0.45 |
0.65 |
0.43 |
0.62 |
0.41 |
0.58 |
|
*Lysine, % |
1.15 |
1.14 |
1.14 |
1.15 |
1.13 |
1.12 |
1.13 |
1.10 |
|
ME = Metabolizable energy; * Determined; ** Calculated;
|
||||||||
|
Table 2: Composition of the broiler finisher diet |
||||||||
|
Level of CPM in the diet, % |
||||||||
|
0 |
0 |
10 |
10 |
15 |
15 |
20 |
20 |
|
|
Maize |
48.0 |
48.0 |
38.0 |
38.0 |
33.0 |
33.0 |
28.0 |
28.0 |
|
Cassava peel |
0.00 |
0.00 |
10.0 |
10.0 |
15.0 |
15.0 |
20.0 |
20.0 |
|
Soybean meal |
25.0 |
25.0 |
25.0 |
25.0 |
25.0 |
25.0 |
25.0 |
25.0 |
|
Blood meal |
0.55 |
0.55 |
1.25 |
1.25 |
1.55 |
1.55 |
2.05 |
2.05 |
|
Fish meal |
2.00 |
2.00 |
2.50 |
2.50 |
3.00 |
3.00 |
3.00 |
3.00 |
|
Palm kernel cake |
5.00 |
5.00 |
4.30 |
4.30 |
4.00 |
4.00 |
4.00 |
4.00 |
|
Wheat offal |
13.5 |
13.3 |
11.7 |
11.5 |
11.0 |
10.8 |
10.3 |
10.1 |
|
Palm kernel oil |
0.50 |
0.50 |
1.80 |
1.80 |
2.00 |
2.00 |
2.20 |
2.20 |
|
Oyster shell |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
1.50 |
|
Dicalcium phosphate |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
3.00 |
|
Common salt |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
|
Methionine |
0.20 |
0.40 |
0.20 |
0.40 |
0.20 |
0.40 |
0.20 |
0.40 |
|
Lysine |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
0.20 |
|
Vitamin/min Premix# |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
|
Analysis, DM basis |
||||||||
|
*Crude protein, % |
20.7 |
20.6 |
20.3 |
20.1 |
20.2 |
20.1 |
20.2 |
20.1 |
|
**ME, Kcal/kg |
2783 |
2773 |
2746 |
2737 |
2708 |
2704 |
2644 |
2637 |
|
*Crude fibre,, % |
3.40 |
3.40 |
4.40 |
4.40 |
4.90 |
4.90 |
5.40 |
5.40 |
|
*Methionine, % |
0.47 |
0.66 |
0.44 |
0.63 |
0.42 |
0.61 |
0.40 |
0.60 |
|
*Lysine, % |
1.16 |
1.15 |
1.15 |
1.14 |
1.13 |
1.12 |
1.11 |
1.10 |
|
ME = Metabolizable energy; * Determined; ** Calculated;
|
||||||||
A feeding trial was conducted using eight birds per treatment. The birds were housed in metabolic cages with facilities for feeding, water supply and excreta collection. Birds were allowed three days pre-collection period for adjustment followed by another three days of excreta collection using total collection method. Excreta collected were weighed and oven-dried at 65o C for 48 hours. Dried samples for bird/treatment were pooled together, milled and representative samples drawn and kept in sealed bottles for laboratory analysis.
Data were collected on feed intake, weight gain, feed conversion ratio, mortality and economy of production.
Utilization of dietary proximate components (crude protein, crude fibre, etherextract, NFE) was calculated as 100*(Dietary component-Excreta)/(dietary component)
Eight birds that had their weights close to the mean for the group were selected per treatment for carcass evaluation. The birds were fasted for 24 hours, weighed individually, stunned, bled, scalded, dressed and the dressed carcass weighed. Weights of the internal organs (liver, kidney, gizzard) were also taken after they had been carefully excised and cleaned. Abdominal fat of the birds was also weighed. All weights recorded were expressed as the percentage of the live-weight of the birds.
Samples of the feeds, excreta and cassava peel meal were analyzed for ether extract, crude fibre, ash and nitrogen according to the methods of AOAC (1990). Nitrogen was determined using the micro-Kjedah method and protein calculated using the factor of 6.5. Methionine and lysine contents of the feeds and cassava peel were determined using liquid chromatography technique as described by Ijarotimi and Olopade (2009).
Data were analyzed by two way Analysis of Variance using the General Linear Model (GLM) procedure of SAS (1998). Significance was determined at P<0.05 level and where means were significant, Duncan’s option of the same software was used to separate the means.
The levels of crude protein and crude fibre in the cassava peel were slightly lower than the values of 5.46% and 18.8%, respectively reported by Augustine et al (2011). Variation in the fibre content of cassava peel has been reported to range from 10 – 30% (Ojebiyi et al 2010; Heuzé et al 2013) depending on the method of peeling. The residual hydrocyanic acid content of the cassava peel (22mg/kg) was lower than the value reported by Tewe (1991). Also the methionine and lysine contents of the peel were slightly lower but comparable to the values reported by Heuzé et al (2013). The differences observed in the chemical composition of the cassava peel used in this study and the earlier ones could be due to the difference in cassava varieties, or soil condition or rainfall distribution (Osei and Twumasi 1989).
|
Table 3: Chemical composition of cassava peel meal (DM basis, except for DM which is on air-dry basis). |
|
|
Component |
% |
|
DM |
89.2 |
|
Crude protein |
5.10 |
|
Crude fibre |
16.5 |
|
Ether extract |
3.90 |
|
Ash |
6.40 |
|
NFE |
68.3 |
|
HCN, mg/kg |
22.3 |
|
Methionine |
0.03 |
|
Lysine |
0.11 |
|
NFE=Nitrogen free extract; HCN = Hydrocyanic acid |
|
|
Table 4: Mean values for main effects of level of cassava peel and methionine on growth performance of broilers |
||||||||||
|
Cassava peel, % |
Methionine, % |
|||||||||
|
0 |
10 |
15 |
20 |
SEM |
P |
0.2 |
0.4 |
SEM |
P |
|
|
Initial wt, g |
37.4 |
37.2 |
37.5 |
37.4 |
0.65 |
0.20 |
37.3 |
37.5 |
0.70 |
0.22 |
|
Final live wt, g |
2280a |
2250a |
2240a |
1870b |
0.3 |
0.03 |
2280b |
2380a |
0.3 |
0.03 |
|
Daily gain, g |
40.0a |
39.5a |
39.3a |
32.7b |
3.8 |
0.03 |
34.0b |
40.1a |
3.8 |
0.03 |
|
Feed intake, g/d |
105 |
107 |
103 |
106 |
5.8 |
0.30 |
104 |
106 |
6.0 |
0.31 |
|
FCR |
2.62b |
2.71b |
2.62b |
3.24a |
0.20 |
0.02 |
2.60 |
2.58 |
0.21 |
0.02 |
|
Mortality, % |
2.56 |
2.38 |
2.65 |
2.48 |
0.8 |
0.18 |
2.63 |
2.52 |
0.90 |
0.25 |
|
abcd: means within main effects bearing different superscript along the same row are different at P<0.05) |
||||||||||
The final body weight, average daily LW gain and feed conversion of the birds were depressed at 20% inclusion level of CPM (Table 4). These parameters were however improved when 0.4% methionine was added to the diet. The significant interaction for these parameters between CPM level and methionine supplementataion indicates that broilers can tolerate up to 15% cassava peel meal using 0.2% methionine supplementation but inclusion of 20% CPM will tend to decrease growth unless 0.4% methionine is added. This finding is in line with that of Osei and Duodu (1988) who also reported that the growth of broilers was maintained with broiler diets containing up to 15% cassava peel meal. It however disagrees with that of Egbunike et al (2009) who reported a decrease in the growth of the broilers fed 5% cassava peel meal. The depression observed in these parameters at 20% CPM inclusion at 0.2% methionine supplementation can be attributed to high crude fibre and/or hydrocyanic acid content of CPM. The residual hydrocyanic acid contained in the diet probably reached a threshold level at 20% inclusion level of CPM such that it interfered with nutrient digestion and absorption. Also, the adverse effect of high fibre diet on the growth of broiler chicken has been well documented. High fibre diet has been demonstrated to elicit slow growth in broiler chicken (Krás et al 2013). The improvement that was observed in weight gain of the birds fed diet containing 20% CPM at 0.4% methionine supplementation indicates that its inclusion at this level can be used to enhance the utilization of cassava peel meal-based diet by broilers at 20% inclusion level. This is in line with the findings of Du Thanh Hang et al (2009) who also reported improvement in the production performance of pigs fed diets containing 20% fresh cassava leaves supplemented with 0.2% synthetic DL methionine. This effect was attributed to the detoxifying effect of methionine on hydrocyanic acid (Aniebo 2012).
Feed intake and mortality were not affected by dietary treatment.
|
Table 5: Mean values for interaction effects of level of cassava peel and methionine on growth performance of broilers |
||||||||||
|
0.2% methionine |
0.4% methionine |
|||||||||
|
0 |
10 |
15 |
20 |
0 |
10 |
15 |
20 |
SEM |
P |
|
|
Initial wt, g |
37.4 |
37.2 |
37.5 |
37.4 |
37.3 |
37.5 |
37.2 |
37.4 |
0.70 |
0.20 |
|
Final wt ,g |
2.28a |
2.26a |
2.25a |
1.87b |
2.27a |
2.25a |
2.28a |
2.25a |
0.28 |
0.03 |
|
Daily gain, g |
40.7a |
40.4a |
40.2a |
33.4a |
40.5a |
40.2a |
40.7a |
40.2b |
3.8 |
0.02 |
|
Feed intake, g/d |
106 |
107 |
106 |
103 |
107 |
105 |
104 |
107 |
5.5 |
0.30 |
|
FCR |
2.58b |
2.63b |
2.60b |
3.24a |
2.60b |
2.64b |
2.62b |
2.71a |
0.2 |
0.03 |
|
Mortality, % |
2.65 |
2.61 |
2.55 |
2.63 |
2.58 |
2.47 |
2.50 |
2.40 |
0.8 |
0.13 |
|
ab: means bearing different superscripts along the same row are different at P<0.05 |
||||||||||
The utilization of the dry matter, crude protein, ether extract and nitrogen free extract of the diets that contained 10% and 15% CPM was not different from that of the control group irrespective of methionine level but was depressed at 20% CPM inclusion level (Table 6). Increasing the level of supplementary methionine from 2 to 4% increased these values. Addition of 0.4% methionine to the diet that contained 20% CPM improved the utilization of these nutrients confirming the interaction between CPM level and supplementary methionine (Table 7).
|
Table 6: Mean values for main effects of level of cassava peel and methionine on apparent digestibility coefficients (%) of diets fed to broilers |
||||||||||
|
Cassava peel |
Methionine |
|||||||||
|
0 |
10 |
15 |
20 |
SEM |
P |
0.2 |
0.4 |
SEM |
P |
|
|
Dry matter |
72.6b |
72.3b |
72.1b |
67.8a |
1.2 |
0.02 |
72.6b |
74.9a |
1.3 |
0.03 |
|
Crude protein |
71.3a |
70.9a |
70.7a |
66.8b |
1.30 |
0.02 |
70.2b |
72.9a |
1.2 |
0.02 |
|
Crude fibre |
68.9 |
69.7 |
70.5 |
70.8 |
3.10 |
0.3 |
70.4 |
70.1 |
3.0 |
0.25 |
|
Ether extract |
72.1a |
71.9a |
71.7a |
68.1b |
2.0 |
0.02 |
71.6b |
73.8a |
2.1 |
0.03 |
|
NFE |
75.2a |
74.8a |
73.2ab |
71.1b |
2.05 |
0.03 |
74.9b |
76.1a |
1.0 |
0.02 |
|
ab: means within main effects bearing different superscript along the same row are different at P<0.05;
|
||||||||||
|
Table 7: Mean values for interaction effects of level of cassava peel and methionine on apparent digestibility coefficients (%) of diets fed to broilers |
||||||||||
|
0.2% methionine |
0.4% methionine |
|||||||||
|
0 |
10 |
15 |
20 |
0 |
10 |
15 |
20 |
SEM |
P |
|
|
Dry matter |
72.4a |
72.2a |
72.1a |
67.7b |
72.5a |
72.5a |
72.4a |
72.3a |
1.3 |
0.03 |
|
Crude protein |
71.2a |
70.8a |
70.6a |
66.8b |
71.1a |
70.9a |
70.9a |
70.5a |
1.3 |
0.03 |
|
Crude fibre |
69.3 |
69.6 |
70.3 |
70.5 |
70.2 |
70.3 |
70.4 |
70.1 |
2.0 |
0.02 |
|
Ether extract |
72.2a |
71.8a |
71.6a |
68.1b |
72.5a |
71.9a |
71.7a |
71.5a |
1.45 |
0.02 |
|
NFE |
75.1a |
74.7a |
74.5a |
71.1b |
74.9a |
74.8a |
74.4a |
74.0a |
2.0 |
0.03 |
|
ab: means bearing different superscript along the same row are different at P<0.05 |
||||||||||
The carcass yield and relative weights of the kidneys and liver were not affected by both CPM and methionine inclusion in the diets (Table 8). Also no interaction was observed between CPM and methionine with respect to these internal organs. Abdominal fat decreased with increased level of CPM in the diet. This can be attributed to high fibre content of CPM (Kenneth and Behm 1981). A similar decrease in abdominal fat pad was reported by Hill and Dansky (1954) and Oladunjoye and Ojebiyi (2010) as a result of feeding oat hull and rice bran respectively to poultry. Level of methionine supplementation however had no effect on abdominal fat. Also there was no interactive effect of CPM and methionine was on abdominal fat.
|
Table 8: Mean values for main effects of level of cassava peel and methionine on carcass characteristics of broilers |
||||||||||
|
Cassava peel, % |
Methionine, % |
|||||||||
|
0 |
10 |
15 |
20 |
SEM |
P |
0.2 |
0.4 |
SEM |
P |
|
|
Live weight, kg |
2.25a |
2.24a |
2.23a |
1.90b |
0.02 |
0.02 |
2.24b |
2.37a |
0.21 |
0.03 |
|
Dressed wt., kg |
1.51a |
1.50a |
1.48a |
1.21b |
0.2 |
0.02 |
1.54b |
1.65a |
0.20 |
0.02 |
|
Carcass yield, % |
67.1 |
67.0 |
66.4 |
63.7 |
5.4 |
0.20 |
68.8 |
69.6 |
5.5 |
0.21 |
|
Abdominal fat,% |
0.82a |
0.77a |
0.68b |
0.51c |
0.06 |
0.02 |
0.81a |
0.80a |
0.05 |
0.31 |
|
Liver, % |
2.40 |
2.38 |
2.41 |
2.43 |
0.15 |
0.34 |
2.42 |
2.39 |
0.14 |
0.32 |
|
Kidneys, % |
0.81 |
0.82 |
0.84 |
0.83 |
0.10 |
0.34 |
0.83 |
0.81 |
0.11 |
0.31 |
|
Gizzard, % |
2.75b |
2.78b |
3.21ab |
4.43a |
1.10 |
0.03 |
2.83a |
2.81a |
0.4 |
0.20 |
|
abc: means within main effects bearing different superscripts along the same row are different at P<0.05 |
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Received 13 October 2013; Accepted 7 February 2014; Published 5 April 2014