Rice cultivation generates large amount of crop residues of which only 20% are utilized for industrial and domestic purposes. In most developing countries especially southeast Asia, rice straw is used as part of feeding ingredients for the ruminants. However, due to its low protein content and high level of lignin and silica, there is limitation to its digestibility and nutritional value. To utilize this crop residue judiciously, there is a need for improvement of its nutritive value to promote its utilization through ensiling. Understanding the fundamental principle of ensiling is a prerequisite for successful silage product. Prominent factors influencing quality of silage product include water soluble carbohydrates, natural microbial population, and harvesting conditions of the forage. Additives are used to control the fermentation processes to enhance nutrient recovery and improve silage stability. This review emphasizes some practical aspects of silage processing and the use of additives for improvement of fermentation quality of rice straw.
Corn was inoculated with Lactobacillus plantarum and Propionibacterium freudenreichii subsp. shermanii either independently or as a mixture at ensiling, in order to determine the effect of bacterial additives on corn silage quality. Grain corn was harvested at 32-37% of dry matter and ensiled in a 4 L laboratory silo. Forage was treated as follows: bacterial types: B0 (without bacteria-control), B1 (L. plantarum), B2 (P. freudenreichii subsp. shermanii), and B3 (combination of L. plantarum and P. freudenreichii subsp. shermanii). Each 2 kg of chopped forage was treated with 10 mL of bacterial culture and allowed to ferment for 27 days. The first experiment determined the most suitable wavelength for detection of bacteria (490 nm and 419 nm for B1 and B2, resp.) and the preferable inoculation size (1 × 105 cfu/g). The second experiment analysed the effect of B1 and B2 applied singly or as a mixture on the fermentation characteristics and quality of corn silage. L. plantarum alone increased crude protein (CP) and reduced pH rapidly. In a mixture with P. freudenreichii, the final pH was the lowest compared to other treatments. As a mixture, inclusion of bacteria resulted in silage with lower digestibility than control. Corn silage treated with L. plantarum or P. freudenreichii either alone or mixed together produced desirable silage properties; however, this was not significantly better than untreated silage.
To alleviate adverse effects of heavy metal toxicity, diverse range of removing methods have been suggested, that is usage of algae, agricultural by-products and microorganisms. Here, we investigated lead (Pb) biosorption efficacy by two lactic acid bacteria species (LABs) in broiler chickens. In an in vitro study, Pb was added to culture medium of LABs (Lactobacillus pentosus ITA23 and Lactobacillus acidipiscis ITA44) in the form of lead acetate. Results showed that these LABs were able to absorb more than 90% of Pb from the culture medium. In follow-up in vivo study, LABs mixture was added to diet of broiler chickens contained lead acetate (200 mg/kg). Pb exposure significantly increased lipid peroxidation and decreased antioxidant activity in liver. The changes were recovered back to normal level upon LABs supplementation. Moreover, addition of LABs eliminated the liver tissue lesion and the suppressed performance in Pb-exposed chicks. Analysis of liver and serum samples indicated 48% and 28% reduction in Pb accumulation, respectively. In conclusion, results of this study showed that L. pentosus ITA23 and L. acidipiscis ITA44 effectively biosorb and expel dietary Pb from gastrointestinal tract of chickens.