In-vitro Gas Production Parameters and Degradability of Diets Containing Graded Levels of Stem-Treated Cashew Nut Shell

Four (4) concentrate diets were prepared containing 0%, 10%, 15% and 20% levels of cashew nut shell coded as T1, T2, T3 and T4 samples of the diets were sent to the laboratory for in-vitro gas production and degradability procedure. In-vitro gas production, organic matter digestibility, Metabolizable energy, short chain fatty acids and methane production were measured. Methane production was measured using 24 hours post incubation period. All the in-vitro parameters were not significantly (P>0.05) different. IVGP ranged from 11.33-18.67, ML/200 mg DM. ME ranged from 4.87 5.90 MJ/Kg DM, OMD ranged from 38.17 % 44.37 % SCFA, ranged from 0.21 0.39 μmol and methane production ranged from 5.33 6.67 mL/200 mg DM all the values did not follow any definite trend. The methane production was found to be generally low in all the treatments. It was therefore concluded that the diets were suitable for ruminant feeding and also safe for the environment. Further experiment focusing on the methane production of these diets, was recommended.


INTRODUCTION
In the tropics ruminants are raised mainly on grasses which are poor in nutrients and digestibility, coupled with scarcity during the off season (Babayemi and Bamikole, 2006) there is need to supplement the ruminant diets with a readily available and relatively sustainable by-products as possible sources of protein and energy to increase animal performance.Feed evaluation is an important necessary tool which provide nutritionist necessary information to formulate diets from both physiology and economical points of view in order to maximize animal performance.
It is also valuable for quality control measures against adulteration or sub.Standardization or deficiency in certain nutrients (Aduku, 2004).
Although animal performance is the best index of feed quality, the availability of animal, the cost of feeding and labour involved do not make it routinely practicable.
Therefore animal performance can be estimated from less animal based techniques that measure related parameters such as feed composition, digestibility degradation fermentation and passage which is in-vitro gas production technique.In the gas method, Kinetic of fermentation can be studied on a single sample and therefore a relatively small amount of sample is required or a larger number of samples can be evaluated at a time (Barde et at., 2015).

In-vitro Gas
This study was therefore designed to evaluate the in-vitro gas production parameters and degradability of diets containing graded levels of cashew nut shell.

MATERIALS AND METHODS
The The in-vitro gas production technique was carried out on experimental diets T1, T2, T3 and T4 (diets containing varying levels of cashew nut shell).The following parameters were measured, in-vitro gas production, (IVGP), organic matter digestibility (OMD), metabolizable energy (ME), short chain fatty acids (SCFA) and methane production.
Rumen fluid was obtained from two goats before their morning feeding as described by Babayemi and Bamikole, (2006) using suction tube.The collected rumen fluid was filtered using a four layer of cheese cloth into a thermo flask that had been pre-warmed to a temperature of 39 0 C. The buffer solution used consisted of (g/litre) 9.8NaHCO3+2.77NaPO4+0.57KCl+0.47NaCl+216 mgSO4.7H2O+16CaCl2.2H2O Incubation procedure was as reported by Menke and Steingas (1998) using 120 mL calibrated transparent plastic syringes fitted with silicon tube.200 g of each sample (in tripilicates) was loaded into the syringes, the rumen fluid and the buffer were mixed together in a ratio of 1:2 (v/v) then 30 mL of the inoculums were drawn into a 100 mL plastic calibrated syringe.This was dispensed into the calibrated transparent plastic syringes containing the feed samples under continuous CO2 flushing.
Air bubbles were removed from the syringes by gently tapping the syringe and pushing the piston upwards to expel the air.The silicon tubes on the syringes were properly clipped to prevent escape of gas before placement in the incubator. In

Experimental Design and Statistical Analysis
The experimental design was a completely randomized design (CRD).Data were analyzed by a one-way analysis of variance (ANOVA) and treatment means were compared (separated) (where there were significant differences) using least significant difference (LSD).With the aid of SPSS (2006) Statistical package for social science version 16.0.

RESULTS AND DISCUSSION
The proximate composition and fibre fractions of the experimental diets are summarized in Feed stuffs that show high capacity for gas production have been implicated to increase methanogenesis (Hess et al., 2004).Reduced methane production could also mean that carbon (IV) oxide and hydrogen gases formed during fermentation were converted to acetate instead of methane.Since methane production in the rumen is a wasteful process (Bourn et al., 2005), the lower the methane produced the better.Steele (1996) had reported 8 % energy loss in form of gaseous products of digestion (mainly methane) in ruminants.The quantity of methane produced by livestock is dependent on their size, age, digestive system and quality and quantity of feed consumed.For instance, buffalo, cattle, camels, goats, and sheep emit the greatest quantities of methane 25-118 kg/head/annum for cattle and 5-8 kg /head/ annum for small ruminants.Pseudo-ruminants (horses, donkeys and mules) and monogastrics such as pigs and poultry produce less methane, since their digestion is not so dependent on enteric fermentation.(Bourn et al., 2005).

CONCLUSION
No significant effect on in-vitro gas production, metabolizable energy, organic matter digestibility, short chain fatty acids and methane production of diets containing graded levels of cashew nut shell was observed.

In-vitro
Production Parameters and Degradability of Diets containing Graded Levels of Stem-Treated Cashew Nut Shell.