6543 Emmanuel Ilesanmi Adeyeye et al./ Elixir Appl. Biology 43 (2012) 6543-6549 Available online at www.elixirpublishers.com (Elixir International Journal) Applied Biology Elixir Appl. Biology 43 (2012) 6543-6549 Relationship of the amino acid composition of the muscle and skin of African giant pouch rat ( Cricetomys gambianus ) Emmanuel Ilesanmi Adeyeye 1 and Funke Aina Falemu 2 1Department of Chemistry, Ekiti State University, PMB 5363, Ado-Ekiti, Nigeria. 2Department of Biology, College of Education, PMB 250, Ikere-Ekiti, Nigeria. ARTICLE INFO ABSTRACT Article history: The amino acid composition of the muscle and skin of the matured female African giant Received: 13 December 2011; pouch rat ( Cricetomys gambianus ) was determined on a dry weight basis. The total essential Received in revised form: amino acids ranged from 29.8-41.2 g/100 g crude protein or from 48.6-53.2 % of the total 19 January 2012; amino acid. The amino acid score showed that lysine ranged from 0.73-1.06 (on whole hen’s Accepted: 31 January 2012; egg comparison), 0.82-1.20 (on provisional essential amino acid scoring pattern) and 0.78- 1.14 (on suggested requirement of the essential amino acid of a preschool child). The Keywords predicted protein efficiency ratio was 1.89-2.41 and the essential amino acid index range Amino acid, was 0.84-1.21. The correlation coefficient (r xy ) was positive and significant at r = 0.01 for the Muscle, total amino acids, isoelectric points and amino acid scores (on whole hen’s egg basis) in the Skin, two samples. Comparison of the samples with the muscle and skin amino acid compositions African giant pouch rat. of the Greater Cane Rat showed that positive and significant differences existed at r = 0.01 between their muscles and their skins respectively. Results have good comparison with whole hen’s egg protein. © 201 2 Elixir All rights reserved. Introduction The Gambian pouch rat ( Cricetomys gambianus ), also Family Nesomyidae, Subfamily Cricetomyinae, Genus known as the African giant pouch rat is a nocturnal rat of the Cricetomys , Species C. gambianus , Binomial name: Cricetomys giant pouched rat genus Cricetomys . It is the largest muroid in gambianus Waterhouse, 1840 the world. It is native to Africa (http://en.wikipedia.org/wiki/Gambian-Pouch-Rat). In Africa it (http://en.wikipedia.org/wiki/Gambian-Pouch-Rat). is routinely eaten as bushmeat. It (and other mammals) is The giant rat Cricetomys gambianus ( Okete ) is a common referred to by the pidgin name of “beef”. rodent found around buildings and gardens in many parts of A study carried out in Nigeria showed that the giant rat Nigeria. It digs long deep burrows with several entrances and produces about the same amount of meat as the domestic rabbit 4. stores found there. It eats roots, bulbs, young shoots and fruits. The meat’s nutritional value compares favourably with that of Other types of rats prefer grains. The female and young are domestic livestock and African villagers know how to prepare it communal and live in burrows. Each community consists of by smoking or by salting 5. The African giant pouch rat is a about thirty individuals; male giant rats live apart by themselves. delicacy in Africa; however, no literature is available on the Nests prepared from vegetable matter occur in the terminal amino acids profile of the skin and muscle. The amino acids chamber of the burrow 1. profile of the brain and eyes of African giant pouch rat had been The Gambian pouch rat can grow to be as big as a raccoon published 6. This work was therefore set out to evaluate the and can weigh up to 4 kg. It has very poor eyesight and so amino acids profile of the muscle and skin of the African giant depends on its senses of smell and hearing. Its name comes from pouch rat, the information derived here may also improve the the large, hamster- like pouches in its cheeks. It is not a true rat, information on food composition Tables. but is part of a uniquely African branch of muroid rodents. In its Materials and methods native Africa, this rat lives in colonies of up to twenty or more, Cricetomys gambianus matured female samples were usually in forests and thickets, but also commonly in termite caught in the wild by a local hunter commissioned for the mounds. It is omnivorous, feeding on vegetables, insects, crabs, purpose at Iworoko Ekiti, Nigeria; identified, immersed in hot snails, and other items, but apparently preferring palm fruits and water (10 min), hair removed and the animals dissected. The kernels 2. muscle and skin were then separately removed, washed with Unlike domestic rats, it has cheek pouches like a hamster. distilled water and dried to constant weight; milled into flour These cheek pouches allow it to gather up several kilograms of and kept in a freezer, pending analysis. nuts per night for storage underground. It has been known to The micro-Kjeldahl methods as described by Pearson stuff its pouches so full of date palm nuts so as to be hardly able (1976) 7 was followed to determine the fat-free crude protein. to squeeze through the entrance of its burrows. The burrow The fat was extracted with a chloroform/methanol (2:1 v/v) consists of a long passage with side alleys and several chambers, mixture using Soxhlet extraction apparatus 8. one for sleeping and the others for storage 3. The African giant About 35 mg defatted samples were weighed into glass pouch rat belongs to the Order Rodentia, Superfamily Muroidea, ampoule, 7 ml of 6M HCl added and hydrolysed in an oven Tele: E-mail addresses: [email protected] © 2012 Elixir All rights reserved 6544 Emmanuel Ilesanmi Adeyeye et al./ Elixir Appl. Biology 43 (2012) 6543-6549 preset at 105±5 oC for 22 h. Oxygen was expelled in the Determination of the ratio of total essential amino acids ampoule by passing nitrogen gas into it. (TEAA) to the total amino acids (TAA), i.e. (TEAA/TAA), total Amino acid analysis was done by ion-exchange sulphur amino acid (TSAA), percentage cystine in TSAA, total chromatography 9 using a Technicon Sequential Multisample aromatic amino acid (TArAA), total neutral amino acid Amino Acid Analyzer (Technicon Instruments Corporation, (TNAA), total acidic amino acid (TAAA) and total basic amino New York, USA) 10 . The period of analysis was 76 min, with a acid (TBAA) were estimated from the results of amino acid gas flow rate of 0.50 ml/min at 60 oC, and the reproducibility profile. The leucine/isoleucine ratio was also calculated. was ±3 %. Tryptophan was not determined. All data generated were analysed statistically. The statistical The amino acid values were calculated from the analysis carried out included the determination of the grand chromatogram peaks as follows. The net height of each peak mean, standard deviation (SD) and the coefficients of variation produced by the chart recorder of TSM (each representing an percent (CV %). Other calculations made were the simple linear 2 amino acid) was measured. The half- height of the peak on the correlation coefficient (r xy ), coefficient of determination (r xy ), chart was found and the width of the peak on the half-height was coefficient of alienation (or index of lack of relationship) (C A) accurately measured and recorded. and index of forecasting efficiency (IFE) and subjected to Table Approximate area of each peak was then obtained by standards to test for significance difference, the level of 17 multiplying the width at half-height. probability was set a r = 0.01 at n-2 degrees of freedom (df) . The norleucine equivalent (NE) for each amino acid in the Results and discussion standard mixture was calculated using the formula: Amino acid compositions (g/100 g crude protein, cp) for the NE = Area of norleucine peak/area of each amino acid different samples are shown in Table I. Glutamic acid was the A constant S was calculated for each amino acid in the standard most concentrated amino acid (AA) in the samples with values mixture: of 13.0 (muscle) – 7.95 g/100 g cp (skin). This was the exact 18 Sstd = NE std x mol. weight x µMAA std trend in the AA profiles of ostrich, beef and chicken . While Finally the amount of each amino acid present in the sample our Lys levels were lower than in ostrich, beef and chicken 18 was calculated in g/16 N or g/100 g protein using the following (with respective values of 8.48, 9.12, 8.96 g/100 g cp); muscle formula: (7.01) and skin (5.94) in turkey hen 19 ; our levels of Lys was Concentration (g/100 g protein) = NH x W@ NH/2 x S std x C better than in the muscle and skin of Greater Cane Rat Dilution x 16 (Thryonomysswingerianus ) with respective levels of 5.19 and C = 4.01 g/100 g cp 20 .Our His levels were close to 2.06-2.25 g/100 g ÷NH x W (Nleu) cp in Greater Cane Rat 20 ; 2.03 in ostrich, beef (3.20), chicken Sample wt (g) x N % x 10 vol. loaded (3.04) 18 ; turkey-hen: muscle (2.60) and skin (2.47) 19 . Phenylalanine levels (4.11-3.50 g/100 g cp) were close to these Where: NH = net height literature values (g/100 g cp): ostrich (4.84), beef (4.48), chicken W = width @ half-height and (4.48) 18 ; turkey -hen: muscle (4.79) and skin (3.80) 19 ; Greater Neu = norleucine Cane Rat: muscle (4.05) and skin (4.80) 20 .