CHARACTERISTICS OF THE CARCASS AND NUTRITIONAL VALUES OF BREED GRASSCUTTER MEAT (THRYONOMYS SWINDERIANUS) FED WITH PELLETS IN BENIN

F. F. Aizoun 1,2* , S. C. B. Pomalegni 1 , C. D. S. J Gbemavo 3 , A. K. I. Youssao 4 , S. Farougou 2 , G. A. Mensah 1 . 1. Laboratory of Zootechnical, Veterinary and Halieutic Research (LRZV), Centre of Agricultural Research/Agonkanmey (CRA) of the National Institute of Agricultural Research of Benin (INRAB), 01 BP 884 Master recipe, Cotonou, 01 Republic of Benin. 2. Department of Animal Production and health, Biotechnology Research Unit of Production and Animal Health, Polytechnic School of Abomey-Calavi, University of Abomey-Calavi (UAC), 01 BP 2009 Cotonou, Benin. 3. Laboratory of Biomathematics and Forest Estimates (LABEF), Faculty of Agricultural Sciences, University of Abomey-Calavi (UAC), 04 BP 1525, Cotonou, Benin. 4. University of Abomey-Calavi (UAC),Polytechnic School of Abomey-Calavi (EPAC), Department of Animal Production and health, Laboratory of Research in Applied Biology, 01 BP 2009 Cotonou, Benin. ...................................................................................................................... ManuscriptInfo Abstract ......................... ........................................................................ Manuscript History


ISSN: 2320-5407
Int. J. Adv. Res. 4 (12), 816-825 817 Africa in sub-Saharan Africa (Hanotte and Mensah 2002;Hardouin, 1986).Grasscutter breeding or the breed grasscutter (Thryonomys swinderianus) falls within this framework (IEMVT-CIRAD, 1992).Since its inception, grasscutter breeding is booming in Benin with more than 70,000 heads of grasscutters in captivity for more than 3,000 breeders (Mensahet al., 2013).It is a game very hunted in intertropical Africa for its meat appreciated by all and sold expensive compared to the beef, small ruminants and pork of current consumption (Baptist and Mensah, 1986).Vegetation fires and poaching are increasingly decreasing and favoring the replacement of game grasscutter by bred grasscutter (Mensah, 1991).Thus, grasscutter breeding can be suggested as an obvious solution for environmental problems (Karikari and Nyameasem, 2009).
In Benin, the breed grasscutters are mainly fed with a wide range of dry and fresh fodder with dietary supplements composed of energetic, nitrogen, vitamin and mineral matter (Mensah 1995;Tolebaet al., 2009).Some breeders supplement fodder with crop residues, agro-industrial products and kitchen remnants.However, faced with all-season feeding problems faced by growers, the production of complete pelleted feed can be the sustainable solution for feeding the grasscutters in captivity (Aïzounet al., 2015).Several studies on grasscutters in captivity have led to significant advances in feeding, reproductive control, zootechnical performance, ethology, age determination (Mensah, 2000, Sacramento et al., 2013, But few were devoted to the nutritional values of grasscutter meat, especially fed with pellets feed.The purpose of this study is to evaluate the characteristics of the carcass and to determine the nutritional values of grasscutter in captivity fed with pellets foods based on green fodder, maize products and by-products and other Food ingredients.

Material and methods:-Study sites:-
The experiment was conducted in a grasscutter place of rearing of Non-Conventional Animal Species Breeding Sub-Programm (S-PEEANC) of Zootechnical Veterinary and Halieutic Research Laboratory (LRZVH) in Agricultural Research Centre of Agonkanmey (CRA-Agonkanmey) in National Institute of Agricultural Research of Benin (INRAB) located in Commune of Abomey-Calavi. The climate is type Guinean, with two dry seasons and two rainy seasons. The average rainfall is 1.200 mm per year and average monthly temperatures vary between 27 and 31°C with relative humidity fluctuates between 65 % from January to March and 97% from June to July. The monthly average was between 27 and 31°C with a deviation of 3.2°C between the hottest month (March) and the least hot (August). Experimental device and data collection:-27 experimental grasscutters aged 7-month were used, divided into three groups with a live weight of 1928.4 ± 51.99 g; 2286 ± 59.52 g and 2077.6 ± 46.05 g respectively.The enclosures of rectangular shaped stage 3 levels were used for the conduct of grasscutter. The pens are divided into two compartments of size (0.7 mx 0.7 mx 0.4 m) communicated with a square opening of 0.2 m square drilled in a median wall and on the floor. This opening allowed the free passage of grasscutter from one compartment to another. For the experiment, the communication openings of the enclosure were closed by bricks to isolate animals. Each enclosure was equipped with feeder and waterer.
The 27 grasscutters were divided into three groups of nine (09) grasscutters and divided into three under-groups of three grasscutters. The device is a complete random block. Each block is made up of three subgroups or observation units.Each block received the three granulated foods with one granule per subgroup in the block.After subdividing them into a subgroup, the grasscutters underwent a food transition phase of ten (10) days following the recommendations made by Mensah and Ekué (2003).Food distribution occurred only once in the morning around 8 am. The water was served at ad libitum in the drinking troughs and renewed every day.

Production of pellets:-
After picking, the fodders were cut, dried in the shade. These fodder plants were crushed at the mill. Other food ingredients including maize grain, wheat bran, rice bran, cassava chips, cottonseed meal, soybean meal, the oyster shells and salt were also crushed. All forages and concentrates are placed in a blender to have a homogeneous mixture. The resulting mixture was then placed in an extruder to effect granulation. Three pellets were produced for testing. The pellet 1 consisted of green fodders and food supplements, the pellet 2 consisted of products and byproducts maize and the pellet 3 consisted of green fodders, food supplements and medicinal plants. The proportion and the quantity of ingredients used in the formulas are shown in Table 1.  (AOAC, 2000) and that of crude ash by carbonization slow at oven. The contents of calcium and phosphorus are assayed by atomic absorption spectrophotometry.
Characteristics of the carcass of farmed grasscutters:-Three grasscutters of each group randomly selected and sacrificed at the end of the experiment to analyze the characteristics of the carcass.Before slaughter, the grasscutters were dieters for 24 hours but had access to water.After sacrificing the animals, they were depilated with boiling water, eviscerated, weighed and refrigerated at 4°C for 24 hours to obtain the weight of the cold carcass.The parameters studied are the live weight at slaughter, the weight of the warm carcass, the weight of the cold carcass, the weight of the heart, the weight of the liver, lungs, kidneys, carcass length, yield in hot carcass and cold carcass.The formulas used to calculate the carcass yield variables are as follows:

Statistical analysis of data:-
The descriptive statistic was performed in terms of mean and standard deviation for the data.The Royan-Joiner normality test and the variance equality test were performed to test respectively the normality and the equality of the variances.In the case of normality, an analysis of variance (ANOVA) was performed for the nutrient values of the pellets, carcass characteristics, organ weights and nutritional values of the meat.Otherwise, the nonparametric Kuskal-Wallis test was performed at the 5% threshold.In case of significant differences between the averages for a parameter following the three pellets, the Student Newman &Keuls averaging test was performed at the 5% threshold.The analyzes were carried out with software R3.0.2 (R Development Core Team, 2012. http://www.Rproject.org/).

Results:-Nutrient values of pellets:-
The bromatological analysis of the three pellets gives the nutrient values shown in Table 2.The dry matter and fat content of the three pellets was not significantly different (p>0.05).On the other hand, the content organic matter and total carbon content was significantly different for the three pellets (p<0.05), as well as that for crude protein, crude fiber, total ash, calcium and phosphorus for the three pellets P<0.05).  Table 3 summarizes the characteristics of the carcass in the grasscutters fed with the different pellets.The results showed that the slaughter weight of the grasscutters fed with pellets varied from 2796 ± 35.07 g to 2876 ± 55.95 g.The difference between the slaughter weight of the grasscutters fed with the different pellets was not significant (p>0.05).The warm carcass weights obtained from the grasscutters fed with pellets were 2876 ± 55.95 g, 2796 ± 35.07 g and 2844 ± 64.26 g, respectively.The difference was not significant between the weight of the warm carcass of grasscutters fed with pellets 2 and 3 as well as the grasscutters fed with pellets 1 and 3 (p>0.05).On the other hand, this difference between the weight of the warm carcass of the grasscutters fed with the pellets 1 and 2 is significant (p<0.05). The same holds for the weight of the cold carcass (p<0.05).The cold carcass yield of the grasscutters ranged from 61.13 ± 1.44% to 63.99 ± 1.93%without significant difference (p>0.05).The hot carcass yield of grasscutters fed with pellets ranged from 64.22 ± 2.09% to 70.75 ± 2.22%.The difference between the warm carcass yields of the grasscutters fed with pellets 1 and 3 was not significant (p>0.05).On the other hand, this difference was significant between the warm carcass yield of the grasscutters fed with pellets 1 and 3 compared to grasscutters fed with pellets 2 (p<0.05).Carcass length 27.82 ± 0.58 cm was obtained in grasscutters fed with pellets 1; 27.3 ± 0.47 cm and 26.46 ± 0.57 cm were obtained in grasscutters fed with pellets 3 and pellets 2 respectively. No significant difference was found between carcass lengths of grasscutters fed with the three pellets (p>0.05).  Table 4 shows the weight of certain organs of grasscutters fed with the pellets produced.The heart weight of grasscutters fed with pellet 1 was highest (20.4 ± 1.82 g) and that of grasscutters fed with pellet 2 was the lowest (13.2 ± 1.30 g).The highest liver weight 18.6 ± 1.95 g was obtained in grasscutters fed with pellet 3 and the lowest 12.8 ± 1.92 g was recorded in grasscutters fed with pellet 1. The kidney weight recorded in grasscutters fed with the three pellets varied from 9.2 ± 1.30 g to 10.4 ± 1.14 g.The lowest lung weight 12.4 ± 1.14 g was obtained in grasscutters fed with pellet 2 and the high 14.2 ± 0.84 g was recorded in grasscutters fed with pellet 1. The difference was significant between the heart weight of the grasscutters fed with the three pellets (p<0.05).The same applies to the weight of the liver and the weight of the lung.On the other hand, the difference was not significant between the kidney weight of the grasscutters fed with the three pellets (p>0.05).  Table 5 shows the nutrient values of the meat of grasscutters fed with pellets.The analysis of the results shows that the dry matter and total ash in the meat of the grasscutters was not significantly different between the three pellets (p>0.05).The difference between the moisture, protein and fat content in the meat of the grasscutters fed with the three pellets was significant (p<0.05).  822

Effects of pellets on the characteristics of the carcass of grasscutters:-Slaughter weight and carcass of grasscutters:-
The slaughter weight of the grasscutters fed with the types of pellets is 2876 ± 55.95 g, 2796 ± 35.07 g and 2844 ± 64.26 g respectively for pellet 1; pellet 2 and pellet 3.These weights at slaughter are superior to slaughter weights 2450g, 2223g, 1887g obtained in grasscutters fed on concentrated feeds containing different levels of Panicummaximun (Karikari and Nyameasem, 2009

Impact of pellets on the weight of Lung, Liver, Kidney and Lung Organs of Grasscutters:-
The heart weights of the grasscutters fed with the three pellets in this study are comparable to those found in the literature.Its heart weights are similar to the 15.45 g, 19.10 g and 21.45 g found by Seiduet al. (2016). They are greater than 11.0 g; 12.0 g and 12.8 g found for the heart weight by Nyameasem (2010) and 10.45 g, 9.18 g and 8.14 g reported by Henry et al. (2012).However, they are less than 23 ± 0.005 g obtained by Omoleet al. (2005).
The liver weights of the grasscutters fed with the three pellets are less than 77 ± 0.023 g reported by Omoleet al.  (1999b).They are also lower than the rates included between 11.92% and 12.64% found by Wogaret al. (2013).But the values obtained in this study are higher than those included between 0.90% and 2.09% recorded by Pokuet al. (2013); to 4 ± 0.13% in the female and 1.5 ± 0.16% in the male to the wild grasscutter obtained by Ella et al. (2014) and values varying between 1.6% and 3.12% reported by Seiduet al. (2016).The total ash obtained in meat of grasscutters fed with pellets is higher than the 0.92%, 1.14% and 0.85% ash levels reported by Pokuet al. (2013) and 0.5%, 0.61% and 0.63% obtained by Seiduet al.
(2016).They are also greater than 1 ± 0.1% in the female and 1 ± 0% in the male for wild grasscutters reported by Ella et al. (2014).

Conclusion:-
All the results obtained during this study show that the pellets produced have a positive influence on the carcass yield, the weight of the organs and the nutritional quality of the meat of the grasscutters which consume them.The meat of grasscutters fed with the various pellets has appreciable nutritional characteristics.Meat of animals fed with the pellets based from green fodder, maize products and by-products, and medicinal plants has a lower fat content and higher protein content compared to meat of grasscutters fed with the pellets based from green fodder pellets, products and by-products of maize, and other food ingredients.The production and use of these pellets in grasscutter breeding will make it possible to raise grasscutters with a meat of good nutritional qualities.