EVALUATION OF MEAT QUALITY OF WEANED RABBITS ADMINISTERED DIFFERENT CONCENTRATIONS OF PROBIOTIC STRAIN ( Saccharomyces boulardii )

The meat quality and sensory properties of weaned rabbits administered different concentrations/cell count of probiotic Saccharomyces boulardii (flora norm) were investigated. A total of 36 mixed breeds of rabbits were randomly divided to four treatments with three replicates and three rabbits per replicate. The weaned rabbits were fed the same diet. Treatments T1, T2, T3 and T4 had zero (0) concentration/cell count of probiotic, 1ml each of 160 x10 it is%1.6 x 10 cfu/ml concentration of probiotic, 1 ml each of 80 x10cfu/ml =8.0 x 10 cfu/ml of probiotic and 1 ml each of 40 x 10cfu/ml concentration of probiotic, respectively. The administration of the probiotic was done once every 14 days. Results obtained showed that there was no significant difference in moisture and crude protein content of meat from rabbits while ether extract differed significantly (P<0.05). The physical properties, cooking yield, cooking loss and water holding capacity were not significantly (P>0.05) influenced by concentrations of probiotics while pH and thermal shortening were significantly (P<0.05) influenced. All the sensory parameters measured were significantly (P<0.05) different. It was found that oral administration of probiotic Saccharomyces boulardii (flora norm) at 4 mg/ml 80 x 10cfu/ml concentration improved meat qualities and overall acceptability of rabbit meat.


Introduction
The anticipated increase in the world's population is to have a severe consequence on food intake especially animal protein intake.According to Delgade et al. (2001), the yearly requirement for animal protein in the third world is projected to increase from 11million tons in 1997 to 213 million tons in 2020.This requirement for meat as well as the financial difficulty experienced by the people in the third world is motivating larger attention to rapid growing animals as well as short production interval likes rabbits (Aduku and Olukosi, 1990).The demand for safe and quality meat in the market has considerably increased.The producers are eager to use natural and nonchemical supplements which positively affect the animal health, increase productivity and improve meat.
The word probiotic was in 1953 introduced firstly by Kollath (Isolauri et al., 2002).Several meanings have been written for the word "probiotic".The most generally recognized one is "live microorganisms which, if added in sufficient quantity, promote health on the host" (FAO, 2003).Application of probiotics can lead in increase of the carcass output and water holding capacity and decrease the meat hardness (Ceslovas et al., 2005).In animal nutrition, microorganisms used as probiotic were linked with a proven efficacy on the gut microflora.Administration of probiotic in feed significantly improves the feed intake, feed conversion ratio, daily weight gain and total body weight in pig, chicken, sheep, goat, cattle and equines (Samli et al., 2007).Several probiotic strains have been utilized for fermented sausages such as lactic acid producing bacteria, mainly Lactobacillus, Pediococus and Streptococcus (Hammes and Knauf, 1994).In many countries of the world, particularly in Europe, the use of antibiotics in animal food is now banned as a result of residues in meat and meat products, and increase in bacteria resistance in human population.As a result of this, coupled with the increased pressure by consumers and agencies of government to decrease and even eliminate the usage of antibiotics in food producing animals, the usage of antibiotics as growth promoting agent has been banned.This action now created the need to find an alternative for the maintenance of health and production in livestock.This has led to the concept of using probiotics to replace antibiotics (Fuller, 1997).Therefore, the aim of this study was to evaluate meat quality of weaned rabbits administered different cell count of strain Saccharomyces boulardii (flora norm).

Materials methods
The experiment was conducted at the rabbitry section of the Teaching and Research Farm of the Department of Animal Production, School of Agriculture and Agricultural Technology, Federal University of Technology Minna, Niger State, Nigeria.Minna lies between the Latitude 9° 31 and 9 o 45 North, and Longitude 6°31 and 6 o 45, East of the equator (Usman, 2011).

Experimental rabbits and their management
The weaned rabbits were bought from the National Veterinary Research Institute (N.V.R.I) Vom, Plateau State, Nigeria.The rabbits were mixed breeds.They were fed with concentrates, forages and clean drinking water ad-libitum.The concentrate were pelletized grower mash (Vital feeds, Grand Cereals and Oil Mills Limited, Jos, Nigeria).The forages used were Tridax, Stylosanthes and cabbage.A day after their arrival, they were given Ivomectin at 0.3 ml subcutaneously against both ecto and endo-parasites.Completely randomized design (CRD) was used for the research.The experiment consisted of four treatments; each treatment had three replicates with each replicate having three rabbits.Treatment one (T 1 ) represented zero level of probiotic, treatment two (T 2 ) represented 8 mg/ml (160 x10 6 cfu/ml) of probiotic, treatment three (T 3 ) represented 4 mg\ml (80 x10 6 cfu/ml) of probiotic while treatment four (T 4 ) represented 2 mg/ml (40 x10 6 cfu/ml) of probiotic respectively.The probiotic was administered orally using a syringe at 1ml per rabbit once every two weeks.The experiment lasted for 8 weeks (56 days).The meat quality characteristics of rabbits were determined according to the method of Awosanya (1989).The slaughtering method was approved by the authorities of the Federal University of Technology Minna.After the conclusion of the growth experiment, 12 rabbits were randomly selected from the four treatments, one rabbit from each replicate.Their final live weights were determined and recorded, then fasted overnight by allowing the animals' access to water only.They were then slaughtered using a knife by means of cutting through the jugular vein and carotid artery around the atlas bone.The rabbits were suspended with the head facing down-ward for 20 minutes to ensure complete bleeding.The changes in the shrunk weight and the weight after bleeding were taken as the blood loss.The rabbits were dressed by complete removal of their hairs, skins (pelts); and were cut at the atlanto-occipital joint.The rear legs were cut at the junction linking the tibia calcaneus while the front legs were severed close to the carpal area and the tail (near the base) removed, and their weights taken separately to accomplish evisceration.The meat quality characteristics were determined.

pH of rabbit meat
The pH of meat samples were determined according to the method of Marchiori and deFelicio ( 2003) using a pH meter (Model 191,Knick,Berlin Germany).A 10 g sample of meat was homogenized in 90 ml distilled water using a blending machine (model 242, Nakai, Japan) at speed 5.The pH meter was standardized using buffers 4 and 7, after which the pH reading of the meat samples were taken.

Water holding capacity (WHC)
The water holding capacity of meat samples were determined using the method described by Kauffman et al. (1992).A section of the meat from the chunk and shank were cut, weighed and kept in a container.Water holding capacity was carried out by cutting a portion of meat weighing approximately 10 g.The sample was pressed using a screw jack until all the free water was expelled.The meat sample was then removed, unwrapped and re-weighed.The difference in weight of meat sample represents the weight of expelled fluid and expressed as a percentage of the initial sample weight and recorded as water holding capacity of the meat.

Cooking yield and cooking loss
The cooking yield and cooking loss were determined using the method described by Kauffman et al. (1992).A portion of the chuck and Shank were selected for broiling.Broiling was done in an open gas oven.The racks were covered with perforated aluminum foils for ease of drainage; the oven was preheated for 5minutes, before loading samples, which was boiled to a temperature of 72 o C as measured with a skewer meat thermometer.The sample was allowed to cool to room temperature, excess fluid was mopped up with paper serviette and their weights were taken and recorded.The difference between the pre-cooked weight and post weight was the cooking loss.While the cooking yield was calculated as cooked weight/thawed weight x100.

Sensory Evaluation of Meat from the Hind Limb of Rabbits
Lean meats from the hind limb from each treatment group were used to evaluate the sensory attributes.Various cuts of the meat were made into bite sizes and boiled in water without salt at 80 0 C for 10 minutes.The meat samples were left to cool to room temperature and then served in coded plates to a 20-member panelist comprising of staff and students of Federal University of Technology Minna, Nigeria who are familiar with rabbit meat.The order of presentation of the samples to the panelist was randomized.The Panelists were instructed to evaluate the meat for appearance, taste, juiciness, chewiness, texture, aroma and overall acceptability on a 9-point Hedonic scale (where 1= dislike extremely and 9=like extremely).Panelist were served with cold water after each evaluation of the meat sample to rinse their mouth to avoid carryover effect during sensory evaluation.

Proximate Composition
The moisture, crude protein and ether extract content of meat samples from the hind limb were determined according to AOAC (2000) method.

Statistical analysis
Data obtained were subjected to analysis of variance (ANOVA) and differences among means were compared Duncan's Multiple Range Test at 5% probability level.All computations were made by statistical software SPSS (version 6).

Results
The meat quality of weaned rabbits orally administered different doses of probiotic (Saccharomyces boulardii) is presented in Table 2.The table revealed that the cooking yield, cooking loss and the water holding capacity of the rabbit meat were not significantly (P>0.05)influenced by the count cell of probiotic (Saccharomyces boulardii).However, the pH values and the thermal shortening of the rabbit meat were significantly (P<0.05)influenced by the different cells count of probiotic (Saccharomyces boulardii).The pH of rabbit meat in T 1 (6.79) and T 3 (6.75)are similar but significantly (P<0.05)higher than those of T 2 (6.63) being the least.Furthermore, the outcome revealed that the thermal shortening was significantly (P<0.05)higher in T 1 (5.42%), and the least value for thermal shortening was obtained in T 3 (1.70 %).The proximate composition of the meat of rabbits orally administered probiotic (Saccharomyces boulardii) is shown in Table 3.The result revealed that different cells count of probiotic (Saccharomyces boulardii) orally administered to the weaned rabbits did not significantly (P>0.05)influenced the moisture and crude protein content of the rabbit meat.However, the ether extract of the rabbit meat was significantly (P<0.05)influenced by the different cells count of the probiotic.The result showed that ether extract was significantly (P<0.05)higher in meat of weaned rabbit in T 3 (9.51%),but statistically (P>0.05)similar to those in T 4 (8.49%), while the lowest ether extract was obtained in meat sample of the weaned rabbit in T 1 (6.31%).The sensory evaluation of rabbit meat orally administered probiotic Saccharomyces boulardii is shown in Table 4.All sensory items studied were significantly (P<0.05)influenced by various cell counts of probiotic Saccharomyces boulardii orally administered to the weaning rabbit.The result showed that all the parameters measured (colour, tenderness, juiciness, flavour and over all acceptability) had a similar trend.The meat from rabbits orally administered probiotic (80 x 10 6 cfu/ml=8.0x 10 7 ) in T 3 had the highest sensory scores compared to all other treatments which are similar.= 0 ml of probiotic Saccharomyces boulardii T2 = 1ml of 160 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally T3 = 1ml of 80 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally T4 = 1ml of 40 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally SEM = Standard error of mean LS = Level of significant N/S = Not significant by various superscript are significantly differing ( P < 0.05) T1 = 0 ml of probiotic Saccharomyces boulardii T2 = 1ml of 160 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally T3 = 1ml of 80 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally T4 = 1ml of 40 x 10 6 cfu/ml of probiotic Saccharomyces boulardii administered orally SEM = Standard error of mean LS = Level of significant

Discussion
The non-significant differences in water holding capacity, cooking yield and cooking loss among various inclusion rates of Saccharomyces boulardii is in line with the result of Pelicano et al. (2003).The authors reported no difference in water holding capacity and cooking loss among different levels of probiotic tested.Contreras -Castillo et al. (2008) reported that lower water holding capacity is an indication of nutrient loss in the exudates, resulting in a tough and less tender meat.The authors also reported a significant difference in pH.The result was in agreement with the findings of Bonai et al. (2008).The authors in a study used a different doses of probiotic Bacillus cereus vartoyoi reported pH values of 6.3 -6.8 of the rabbit meat which falls within the pH values obtained in our study.
The values of moisture content and crude protein observed in the current study falls within the values (63.6 -76.8% moisture, 20.38 -29% crude protein and 0.33 -14.6% ether extracts reported by Pla et al. (1996).The significant effect on ether extract could have been due to manipulation in nutrition for domesticated rabbit as reported by Olorunsanya et al. (1999) andJiya (2012).The authors observed that the hare rabbits solely survive on herbs in the wild, which could have been responsible for the higher percentage of fats normally observed with the domesticated rabbits.The highest scores for colour, tenderness, juiciness, flavour and overall acceptability in the result of rabbit meat administered 1ml of 80 x 10 6 cfu/ml of probiotic ( Saccharomyces boulardii) agrees with the reports of Savković et al. (2005).The authors reported improvement for juiciness, as well as the tenderness in the sensory attributes of meat administered probioticsupplemented diets.

Conclusion
Oral administration of probiotic strain Saccharomyces boulardii (flora norm) at 80 x 10 6 cfu/ml concentration/ cell counts improved meat qualities and overall acceptability of rabbit meat.