| Livestock Research for Rural Development 20 (2) 2008 | Guide for preparation of papers | LRRD News | Citation of this paper |
A seventy-day feeding trial was conducted with one hundred and twenty 7-day old Anak 2000 broiler chicks to study the effects of fermentation of sweet orange (Citrus sinensis) fruit peels on its replacement value as a dietary energy source. Sweet orange peels fermented for duration of 0, 24 and 48hrs and thereafter dried and ground were used to each replace maize in the control diet at 30% level. The chicks were divided into four groups, each group replicated three times at the rate of ten chicks per replicate. A group each was assigned to one of the four isonitrogenous diets: CD (control), SP0D SP24D and SP48D, compounded. The performance, carcass quality and weights of the visceral organs were evaluated.
Fermentation of sweet orange peels depressed the mean feed intake, body weight gain and live weight of broilers among the treatment groups highly significantly (p < 0.01) the longer its duration. The performance of broilers in the orange peel based diets was inferior to the control. Fermentation of sweet orange peels caused significant disproportionate growth in % live weight of shoulder (p < 0.05) and neck + back (p < 0.01). Utilization of sweet orange peels significantly reduced (p < 0.05) the % live weight of the abdominal fat thus improving the nutritive value of the meat. Kidney was the only visceral organ significantly affected (p < 0.05) by the diets.
The fermentation procedure in this study has proved inadequate to harness the nutritional potential of the sweet orange fruit peel.
Keywords: carcass quality, chicks, performance, sun drying
Livestock plays an important role in Nigeria agriculture contributing 9.88% of the agricultural gross domestic product (CBN, 2003). The 2001 population of livestock in Nigeria has been estimated to be 118.59m poultry, 45.26m goats, 28.69m sheep, 15.60m cattle, 5.25m pigs, and 1m horses, camels and donkeys (National Planning Commission, 2004). Despite this enormous resource, a wide gap exists between demand and supply. It has been reported that the daily animal protein intake per caput in Nigeria is about 8g which is far below the required 35g protein intake requirement of animal origin out of the 70g daily recommended total protein intake (Obioha, 1992). One of the major reasons for the low level of animal protein intake in the tropics and in Nigeria in particular is because livestock production is not keeping pace with human population growth rate put at 3.2% (NPC, 2006). Another critical reason is the scarcity of conventional food stuff (energy and protein sources) for monogastric animal feeding and consequently the cost of livestock feed. In Nigeria, feed cost is estimated to be over 70% of the total cost of intensive livestock production. The search for alternative feed resources which are less competitive, not expensive and can be efficiently converted by farm animals to meat and other consumable animal products for the enhancement of animal production has therefore become of great interest.
The poultry industry is one fast means of providing the much needed animal protein to the teeming populace. It has been suggested that the expansion of the Nigeria poultry holds the greatest promise of bridging the animal protein gap in the country within the shortest possible time (Dafwang, 1990). Some agro-industrial by-products like maize offal, cocoa husk meal, rice offal, brewer dried grain have been used in poultry diets to replace cereals (Uko et al 1990; Sobamiwa and Akinwale, 1999; Udedibie and Emenalom, 1993) Broiler birds are probably the most universal and important of all poultry as producers of meat for human consumption. It has been reported that sweet orange (Citrus sinensis) peel meal obtained from ground sun dried peels can replace dietary maize in broiler chicken diet at 20% level without any adverse effect on performance (Agu, 2006). Feed processing helps to enhance the feeding quality of agro-industrial by-products by reducing the level of toxicants where present, improving their nutrient value, acceptability of feed, and utilization by animals. This study therefore investigated the effect of the fermentation of fresh sweet orange fruit peel on its maize replacement value in broiler chickens.
The study was conducted in the Poultry experimental unit housed within the Livestock section of the Teaching and Research Farm University of Agriculture, Makurdi, Nigeria. A total of one hundred and twenty healthy 7-day old Anak 2000 broiler chicks purchased from Obasanjo Farms were randomly divided into four dietary groups each containing thirty birds. Each group had three replicates and ten chicks per replicate. The dimension of each replicate pen was 164cm x 83cm. The composition of the experimental diets is in Table 1.
|
Table 1. Composition of the experimental diets, % |
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|
Ingredients |
Starter Diets |
Finisher Diets |
||||||
|
CD |
SP0D |
SP24D |
SP48D |
CD |
SP0D |
SP24D |
SP48D |
|
|
Maize |
44.43 |
31.10 |
31.10 |
31.10 |
51.61 |
36.13 |
36.13 |
36.13 |
|
FFSM |
42.62 |
42.62 |
42.62 |
42.62 |
35.44 |
35.44 |
35.44 |
35.44 |
|
SOFPM |
0 |
13.33 |
13.33 |
13.33 |
0 |
15.48 |
15.48 |
15.48 |
|
BDG |
6.50 |
6.50 |
6.50 |
6.50 |
6.50 |
6.50 |
6.50 |
6.50 |
|
Blood meal |
2.00 |
2.00 |
2.00 |
2.00 |
2.00 |
2.00 |
2.00 |
2.00 |
|
Bone meal |
3.50 |
3.50 |
3.50 |
3.50 |
3.50 |
3.50 |
3.50 |
3.50 |
|
Common Salt |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
|
Premix* |
0.20 |
0.20 |
0.20 |
0.20 |
0.25 |
0.25 |
0.25 |
0.25 |
|
Methionine |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
|
Lysine |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
|
Total |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
Calculated nutrients, % DM |
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|
Crude protein |
23.50 |
23.32 |
23.44 |
23.67 |
21.41 |
21.19 |
21.32 |
21.59 |
|
Crude fibre |
3.99 |
5.47 |
5.61 |
5.71 |
3.95 |
5.53 |
5.69 |
5.80 |
|
Ether extract |
9.94 |
9.71 |
9.74 |
9.79 |
8.93 |
8.67 |
8.63 |
8.78 |
|
ME, kcal/kg |
3241 |
2987 |
2994 |
3025 |
3235 |
2940 |
2949 |
2985 |
|
Calcium1 |
1.41 |
1.41 |
1.41 |
1.41 |
1.40 |
1.40 |
1.40 |
1.40 |
|
Phosphorus2 |
0.88 |
0.87 |
0.87 |
0.87 |
0.85 |
0.85 |
0.85 |
0.85 |
|
FFSM = Full fat soybean, SOFPM = sweet orange fruit peel meal, BDG = brewer dried grain *Vitamin/mineral premix, 1, 2 Values did not include the contribution from SOFPM |
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The test ingredient which was the only variable ingredient was the processed sweet orange (Citrus sinensis) fruit peel. Fresh sweet orange fruit peels were gathered from peeled orange sellers in the University town of Makurdi and divided into three portions. The first portion was sun dried immediately (SP0) while the second portion was tied in synthetic sack for 24 hrs before sun drying (SP24). The third portion was similarly tied, but for 48 hrs before sun drying (SP48). Sun drying in each case took about 48 hrs by which time the peels became crispy. Each of the dried sweet orange peel portions was ground and analysed for its nutrient composition (Table 2).
|
Table 2. Nutrient composition of fermented sweet orange fruit peels, %DM |
|||
|
Nutrients |
SP0 |
SP24 |
SP48 |
|
Dry matter, DM |
85.9 |
87.6 |
89.2 |
|
Crude protein, CP |
7.44 |
8.29 |
10.0 |
|
Crude fibre, CF |
12.9 |
13.9 |
14.6 |
|
Ether extract, EE |
2.29 |
2.50 |
2.95 |
|
Ash |
3.85 |
4.35 |
4.47 |
|
Nitrogen free extract, NFE |
73.5 |
71.0 |
67.9 |
|
Gross energy, kcal/kg |
2440 |
2530 |
2890 |
|
1Metabolisable energy, kcal/kg |
1529 |
1585 |
1812 |
|
1Metabolisable energy = 0.860+0.629(G.E-0.78CF) by Campbell 1986 |
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Each peel meal replaced maize as a dietary energy source at 30% level and added to the other ingredients to compound diets SP0D, SP24D and SP48D, respectively. The control diet (CD) did not contain sweet orange fruit peel meal. The experimental units were fed ad libitum and the birds had free access to cool drinking water daily for the feeding trial which lasted 70 days. Routine management procedures for broiler chickens in terms of sanitary measures, medication and vaccination programmes were adhered too. Feed and water wastages were avoided to guarantee the reliability of feed data from which other performance indices required for valid scientific inferences in this study will be derived and to ensure that the experimental pens were dry. The broilers were weighed weekly to determine the growth rate in each diet group. The corresponding feed intake for each experimental unit was also recorded. The feed conversion ratio (FCR) was obtained from the ratio of feed intake: body weight gain. At the end of the trial (70th day), three broiler chickens were randomly selected from each dietary group for carcass evaluation. Prior to slaughter, the birds were starved of feed for about 18 hrs and individual live weight (LW) taken. Then the head was severed from the rest of the body from the neck. Slaughtered birds were immersed in hot water (about 800C) for about 10 seconds, immediately defethered, eviscerated and cut into carcass parts. The weights of the carcass cuts and internal organs were taken using the Mettler B12001 electronic balance. All weights were expressed as percentage of live weight (LW). Dressing percentage was calculated using the formula recommended by Fielding (1991). The nutrients in the test ingredients i.e. SP0, SP24 and SP48 were determined using the standard methods (AOAC, 1995).
All the performance, carcass quality and visceral organs data obtained in the trial were statistically analysed using one-way Analysis of Variance procedure outlined in Minitab Statistical Software (Minitab Statistical Software, 1991). The means of parameters which were significantly different were separated by applying the least significant difference (LSD) procedure (Steel and Torrie, 1980).
The nutrient composition of the sweet orange fruit peel meals in Table 2 shows that their crude protein (CP), crude fibre (CF), ether extract (EE), ash and gross energy (GE) contents expressed on percent of dry matter (DM) increased from the 0hr to 48hr fermentation duration, whereas the nitrogen free extract (NFE) decreased.
The CP in the peels fermented for 0 and 24hrs were lower than 9.25% CP in maize (Tuleun et al 2005), while 10.04% CP for the peels fermented for 48hrs was higher. The CF in the peels which was in the range of 12.87 to 14.63% DM was comparatively higher than 2.20% CF reported for maize (Tuleun et al 2005). The CF obtained in this study agrees with CF content of 13.66 to 14.99% DM in the peels of some citrus fruit varieties (Oluremi et al 2007). This high peel CF may reduce its feeding value compared to dietary maize in non-ruminant nutrition.
The performance of broiler chickens in the feeding trial is in Table 3. It was observed that the replacement of maize with sweet orange fruit peel meal in the diet affected the live weight (LW), body weight gain (BWG) and feed intake significantly.
|
Table 3. The growth performance of Broilers on experimental diets |
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|
Performance indices |
Experimental Diets |
SEM |
|||
|
CD |
SP0D |
SP24D |
SP48D |
||
|
Initial body weight, g/bird |
72.17 |
73.67 |
74.00 |
72.00 |
5.53NS |
|
Final body weight, g/bird |
2022a |
1398b |
1240b |
1111b |
156** |
|
Feed intake, g/bird |
98.0a |
68.5b |
63.1b |
63.8b |
4.84** |
|
Body weight gain, g/day/bird |
27.9a |
18.9b |
16.7b |
14.8b |
2.21** |
|
Feed Conversion ratio |
3.35 |
3.47 |
3.69 |
3.77 |
0.21NS |
|
Mortality |
1/30 |
0/30 |
0/30 |
0/30 |
|
|
SEM= Standard error of mean NSNot significantly different (p > 0.05) a,bMeans in the same row with different superscripts are highly significantly different (p <0.01) |
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The mean final live weight of broilers in the control group (CD) was 2022g and it was significantly higher (p < 0.05) than 1397g, 1239g and 1110g for chickens in SP0, SP24D and SP48D, respectively. There was no significant difference (p > 0.05) in the live weights of broilers among the treatment receiving the sweet orange peel meal based diets. This implies that the processing of sweet orange peel by fermentation applied in this study has not improved the nutrients quality of the peel to make it a suitable replacement for maize as an energy source in raising broilers. The longer the time for fermentation of the fresh sweet orange fruit peels, the lighter the broiler chickens became. Diet treatment effect on BWG which is a measure of the growth rate of broilers was highly significant (p < 0.01). The birds in the control group had the highest daily BWG of 27.86g/broiler whereas for the orange fruit peel diets, BWG were significantly lower. The growth rates of the experimental chickens were depressed in the diets containing the sweet orange peel meals. This shows that long duration of fermentation of the fresh orange peels resulted in a more adverse effect on BWG. In other words as the length of fermentation of the peels increased from 0hr to 48hrs, daily BWG decreased, from 18.92/bird to 14.84g/bird. This daily BWG range was found to be lower than an average of 25.7g to 33.5g (Oluremi et al 2006) and 38.11g to 58.37g (Agu, 2006) when unfermented sweet orange peel meal substituted maize in the diet of broilers. The effect of the experimental diets on the mean feed intake of broiler chickens was highly significant (p < 0.01). The control group had an average daily intake of 98.02g and it was significantly higher than the intake regime of 63.10g to 68.50g in the sweet orange fruit peel meal based diets. Sweet orange fruit peel contains oil which is acidic and confers on it a sharp taste which may have been responsible for the depression in the quantity of feed consumed by broilers in the SP0D, SP24D and SP48D test groups. The experimental diets did not have any significant effect (p > 0.05) on feed conversion ratio (FCR) of broilers. A progressive decline in FCR as the duration of peel fermentation increased was observed. This is an indication that long fermentation period of the sweet orange peels impairs nutrient utilization in broilers. In the feeding trial, only one chicken from the control treatment died. This mortality rate is lower than 1% which is below a mortality rate of less than 4% regarded as normal for broiler (AERLS, 1987).
Broiler carcass data and the result of the statistical analysis are in Table 4. The effects of the diets on pre-slaughter live weight (LW), dressing percentage, plucked weight, eviscerated weight and the following carcass cuts: thigh, drumstick, breast and wing weights expressed as percent LW were not significantly different (p > 0.05) among the treatment means.
|
Table 4. The Carcass data of Broilers on experimental diets |
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|
Carcass indices |
Experimental Diets |
SEM |
|||
|
CD |
SP0D |
SP24D |
SP48D |
||
|
Pre-slaughter weight, g/bird |
1713 |
1323 |
1157 |
1173 |
235NS |
|
Plucked weight, %LW |
44.8 |
94.6 |
94.6 |
95.1 |
1.54NS |
|
Eviscerated weight, %LW |
81.0 |
78.8 |
76.0 |
77.4 |
2.03NS |
|
Dressing percentage |
77.4 |
75.38 |
71.62 |
73.68 |
2.22NS |
|
Thigh, %LW |
10.7 |
11.1 |
10.2 |
10.6 |
0.59NS |
|
Drumstick, %LW |
11.7 |
11.9 |
10.8 |
10.6 |
0.55NS |
|
Breast, %LW |
18.2 |
17.5 |
16.3 |
16.2 |
1.22NS |
|
Wing, %LW |
4.67 |
4.73 |
4.75 |
5.02 |
0.12NS |
|
Shoulder, %LW |
4.67 |
5.89 |
6.10 |
6.13 |
0.96* |
|
Neck + back, %LW |
17.9 |
15.6 |
15.0 |
15.6 |
0.44** |
|
Abdominal fat, %LW |
1.19 |
0.40 |
0.37 |
0.39 |
0.25* |
|
%LW = percent live weight. SEM = Standard error of mean. NSNot significantly different (p > 0.05). a,bMeans in the same row with different superscripts are significantly different (p < 0.01). |
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This shows that the substitution of maize with sweet orange fruit peel in broiler chicken diet did not have any negative effect on these carcass cuts compared with the control in terms of proportionate growth in relation to live eight. The experimental diets however, had significant effects on shoulder cut (p < 0.05), neck + back cut (p < 0.01) and abdominal fat (p < 0.05) expressed as %LW. As the time lag of peels fermentation increased the shoulder cut showed a significant increase (p < 0.05) while the neck + back cut significantly decreased (p < 0.01). The abdominal fat was observed to be significantly reduced in the sweet orange peel meal based diets. There is the possibility that sweet orange peel possesses some intrinsic factor(s) which do not promote the deposition of fat in the body. In a recent study by Oluremi et al (2007), the presence of saponin in sweet orange peel has been reported, and this compound has been observed to have hypocholestremic action (Oakenfu and Sidhu, 1983). It is known that high carcass fat reduces the economic value of animal meat. It thus appear that if adequate processing techniques to enhance the nutritive value of sweet orange fruit peel can be evolved to enable it promote fast broiler growth rate, then it can be a viable dietary energy substitute for maize in feeding with a view to reducing the cholesterol content of meat.
The result obtained showing the effect of the experimental diets on visceral organs of broiler chicken is in Table 5.
|
Table 5. The weight of visceral organs of Broilers fed experimental diets, %LW |
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|
Visceral organs |
Experimental diets |
SEM |
|||
|
CD |
SP0D |
SP24D |
SP48D |
||
|
Gizzard |
2.90 |
2.35 |
2.99 |
2.82 |
0.33NS |
|
Proventriculus |
0.44 |
0.54 |
0.54 |
0.49 |
0.05NS |
|
Liver |
1.86 |
2.25 |
2.25 |
2.27 |
0.19NS |
|
Heart |
0.44 |
0.46 |
0.39 |
0.52 |
0.05NS |
|
Gall bladder |
0.16 |
0.15 |
0.19 |
0.24 |
0.07NS |
|
Kidney |
0.69b |
0.95a |
1.00a |
0.94a |
0.09* |
|
Spleen |
0.15 |
0.12 |
0.14 |
0.16 |
0.02NS |
|
Lung |
0.80 |
0.63 |
0.68 |
0.88 |
0.10NS |
|
SEM = Standard error of mean. NSNot significantly different (p > 0.05). a,bMeans with different superscript in the same row are significantly different (p <0.05). |
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The % live weight of kidney of the experimental chickens for SP0D (0.95%), SP24D (1.00%), and SP48D (0.94%), were significantly higher (p < 0.05) than 0.69% for CD the control diet. It is hoped that further studies will investigate the cause of this significant kidney weight in view of the critical role this organ plays. The % live weight of proventriculus, gizzard, liver, gall bladder, heart, lung and spleen of broilers on the sweet orange fruit peel diets were statistically comparable (p > 0.05) with the corresponding visceral organ weights in the control diet. This result shows that sweet orange fruit peel at 30% level of maize replacement investigated did not have adverse effect on most of the internal organs. This citrus by-product may therefore not threaten the health of broiler chickens.
The performance data has evidently showed that fermentation of sweet orange (Citrus sinensis) peels depressed broiler performance. However, it did not result in disproportionate growth of most of the carcass cults nor did it jeopardize the health of the birds. The only mortality recorded was the loss of one chicken in the control group. With the exception of the kidney weight, substituting dietary maize with sweet orange peel meal did not produce any significant effect as visceral organ weights. Visceral organs are critical for good health status of broiler chickens just like any other farm animals.
While the nutrient composition of sweet orange fruit peel seems to highlight its potential to serve as an alternative feed stuff to maize, it’s apparent that the fermentation technique employed in the present study is not adequate to transform it into a form that will enhance its usefulness. Further studies are required to discover appropriate processing methods to harness its nutritional potential.
AERLS 1987 Brooding and Rearing of chicks on deed litter floor. Extension Bulletin No.23. Poultry Bulletin Series No.2. AERLS, ABU, Samaru-Zaria, Nigeria
Agu P N 2006 Nutritional Evaluation of Sweet orange (Citrus sinensis) peel as a feed resource for Broiler chickens unpublished M.Sc. Thesis Department of Animal Production, University of Agriculture, Makurdi, Nigeria
AOAC 1995 Official Methods of Analysis, 16th Edition. Association of Official Analytical Chemists, Washington, D.C
Campbell G L 1986 Prediction of Metabolisable energy of Broiler diet: Chemical analysis. Poultry Science 65: 2126-2134
CBN 2003 Annual Report and Statement of Accounts. Central Bank of Nigeria December 2003
Dafwang I I 1990 Poultry Production in Nigeria. A Paper presented at Workshop Organized by the College of Agriculture, Lafia, Nigeria. 1990
Fielding D 1991 Rabbits. The Tropical Agriculturalist. Macmillan Press London with CTA. Pp 61-69
Minitab Statistical Software 1991 Minitab Statistical Software, Rehearse 8.21 Minitab Inc., State College, P.A.
National Planning Commission 2004 New Partnership for Africa’s Development: Comprehensive Africa Agricultural Development Programme. A Draft copy, Abuja, Nigeria
NPC 2006 National Population Census. Abuja, Nigeria
Oakenfu D G and Sidhu GS 1983 A phyto-chemical explanation for the effects of dietary saponins on cholesterol and bile salt metabolism Nutrition Review International 27:1253-1259.
Obioha F C 1992 A guide to Poultry Production in the Tropics. Acena Publication Enugu, Nigeria. Pp139-140
Oluremi O I A, Ngi J and Andrew A I 2007 Phytonutrients in citrus fruit peel meal and Nutritional implication for livestock production. Livestock Research for Rural Development Volume. 9 Article 89. http://www.lrrd.org/lrrd19/7/olur19089.htm
Oluremi O I A, Ojighen V O and Ejembi E H 2006 The nutritive Potential of sweet orange (Citrus sinensis) in Broiler Production. International Poultry Science 5 (7): 613-617
Sobamiwa O and Akinwale T O 1999 Replacement value of Cocoa husk meal for maize in diets of growing pullets. Tropical Journal of Animal Science 1: 111-116
Steel R G D and Torrie J H 1980 Principles and Procedures of Statistics. A Biometrical Approach. 2nd Edition. McGraw-Hill Books Co. Inc., New York
Tuleun C D, Njike M C, Ikurior S A and Ehiobu N G 2005 Laying performance and egg quality of hens fed cassava root meal/brewers yeast slurry based diets. Production Animal Technology, 1: 148-152
Udedibie A B I and Emenalom OO 1993 Preliminary observations on the use of maize – sorghum based dried brewer’s grains fortified with palm oil for finisher broilers. Nigerian Journal of Animal Production 20: 104-109
Uko J O Awoyesuku P and Babatunde G M1990 Substituting value of maize offal for maize in the diet of laying hens. Nigerian Journal of Animal Production 17: 56-59
Received 1 October 2007; Accepted 30 October 2007; Published 1 February 2008