This study was carried out to evaluate the effect of biomodification with the fungi Trichoderma harzianum on the chemical composition as well as the in vitro gas production characteristics of melon seed husk (MH) with or without supplementation with wheat bran (WB). Wheat bran supplemented melon seed husk (0%, 25%, 50%, 75%, 100%) were inoculated with Trichoderma harzianum for 21 days and later dried and milled for chemical analysis and in vitro gas fermentation study. The result showed that supplementation in general was effective in increasing significantly (P < 0.05) the crude protein and decreasing the cell wall fraction. The treatment with Trichoderma harzianum increased the CP from 5.25%, 7.88%, 10.00%, 13.13%, 14.90% for the untreated to 5.70%, 8.32%, 10.95%, 14.90% and 16.20% in the treated form of 0WB:100MH, 25WB:75MH, 50WB:50MH, 75WB:25MH, 100WB:0MH respectively. Although only 75WB:25MH was significantly different (P < 0.05). The value for NDF of the treated ranged from 49.00% for 100WB:0MH to 82.50% for 0WB:100MH. Although only 75WB:25MH and 100WB:0MH had significant decreases (P < 0.05). The value for ADF of the treated ranged from 7.00% for 100WB:0MH to 60.00% for 0WB:100MH and only the decrease of 25WB:75MH was not significant (P > 0.05). The values for hemicelluloses for the treated ranged from 22.50% for 0WB:100MH to 42.00% for 100WB:0MH with only 100WB:0MH having a significant decrease (P < 0.05). Gas volume, DMD, OMD, SCFA were significantly (P < 0.05) higher in the untreated sample values when compared to the treated values. This result suggest that Trichoderma harzianum appears to be a weak fungi in the treatment of agricultural waste to enhance the nutritive value and digestibility.
The major constraint to livestock production in Nigeria is the scarcity of quality and sufficient supply of feed throughout the year. This is more so because of the competition between man and livestock for the available food grains. Added to this is the increasing population at a very high rate, especially in developing countries like Nigeria. With the increasing demand for livestock products in the world economy and shrinking land area, future hope of feeding the nations and safeguarding their food security will depend on their better utilization of the non-conventional feed resources which cannot be used as food for human (Makkar, 2000).
Agricultural wastes and by-products have been used extremely in ruminant nutrition in many parts of the world as substitute for concentrate feeds which are usually very expensive in the developing countries (Akinfemi, 2010a). In Nigeria, there is a wide gap between animal requirement and the available feedstuff. Although a huge tonnage of agriculture waste and by-products are produced annually in Nigeria, only a few fraction are used to feed ruminants while the largest proportion are burnt or discarded leading to environmental pollution and health hazards (Akinfemi, 2010a).
Ruminants are endowed with the ability to convert low quality feed into high quality protein and utilize feeds from land not suitable for cultivation of crop, but however, the utilization of these low quality crop residues are hampered by their low protein content, fibre digestibility, vitamins and minerals. These materials considered as waste could be recycled by environmental friendly methods into ruminant feed by physical, chemical and biological methods. The possibility of biological treatment of agricultural waste and by products has a great potential as an alternative to the use of expensive chemical methods (Abd-Allah, 2007).
The nutritive value of a ruminant feed is determined by the concentration of its chemical components, as well as extent of digestion. Determining the digestibility of feeds in vivo is laborious, expensive, requiring large amount of time and is largely unsuitable for single feedstuff thereby making it unsuitable for routine feed evaluation (Getachew et al., 2004). Consequently in vitro gas production techniques were developed to predict fermentation of ruminant feedstuff. It is a laboratory estimation of degraded feeds which are important in livestock nutrition (Ajayi and Babayemi, 2008). It is a method reproducible and parameters obtained correlate well with in vivo method (Ajayi and Babayemi, 2008). A feedstuff incubated with buffered rumen liquor and gas produced is measured as an indirect indicator of fermentation kinetics (Rymer et al., 2005). It is first degraded and the resulting fraction may either be fermented to produce gas, fermentation acids or incorporated into microbial biomass. When combined with measures of degradation, gas production techniques provides a measure of the proportion of feed that is fermented as opposed to that which is partitioned to microbial growth (Rymer et al., 2005). The principle of determining potential rumen degradability/fermentability of a feed by measuring gas produced from a batch culture was first developed by McBee (1953) and Hungate (1966).
1.1 Research Objectives
The study of the effect of biomodification with Trichoderma harzianum on the chemical composition and in vitro gas production characteristics of sole and supplemented melon seed husk has been designed with the following objectives.
- To determine the effects of biomodification with Trichoderma harzianum on the chemical composition of supplemented and unsupplemented melon seed husk
- To investigate the effects of biomodification with Trichoderma harzianum on the in vitro gas production characteristics of melon seed husk with or without supplements.
- To measure the short chain fatty acid (SCFA) production potential of biomodified melon seed husk with or without supplement.