Lactobacillus plantarum as feed additive to improvement in vitro ruminal biofermentation and digestibility of some tropical tree leaves

AIM

This study was performed to investigate the effects of Lactobacillus plantarum (LP) on the in vitro gas production (GP) kinetics and ruminal fermentation parameter of three species of tropical forage Ziziphus mauritiana, Acacia victoriae and Moringa oleifera.

METHODS AND RESULTS

Treatments were (i) Z. mauritiana (Z) without LP (-ZLP), (ii) Z. mauritiana (Z) with LP (+ZLP), (iii) A. victoriae (A) without LP (-ALP), (4) A. victoriae (A) with LP (+ALP), (5) M. oleifera (M) without LP (-MLP) and (6) M. oleifera (M) with LP (+MLP). The LP was used at 0·5 Mcfarland (1·5 × 10⁸ colony-forming unit per millilitre (CFU per ml)). Kinetic of GP (GP from the fermentable fraction [b], GP rate [c] and lag phase [L]) and GP were affected (P < 0·05) by plant species and LP. The highest value of b, c and GP were observed in +MLP treatment compared with other treatments. The lowest value of L was observed for the +ZLP treatment compared with other treatments. The GP and fermentation parameter included organic matter digestibility (OMD), metabolizable energy (ME) content, microbial CP (MCP) and truly degraded substrate (TDS) were affected by plant species and LP supplementation. The highest OMD, ME, TDS and MCP values were observed in +MLP treatment. At different incubation times, the highest amount of ammonia-N was observed in treatment +MLP compared with other treatments. Under the influence of experimental treatments (effect of plant species and LP), the highest concentrations of total volatile fatty acids, acetate and acetate to propionate ratio were observed in treatments +MLP, +ALP and +ALP, respectively. Concentrations of propionate, iso-butyrate, n-valerate and iso-valerate were affected by plant species, and the highest levels were observed in -ZLP, +MLP, -MLP and +MLP tretments, respectively.

CONCLUSIONS

The use of LP as a microbial additive had a positive effect on the in vitro digestibility and ruminal fermentation of tannins-rich tropical plants. Results suggest that dietary LP inclusion could be an option to improve ruminant energy utilization efficiency of tannins-rich tropical plants.

SIGNIFICANCE AND IMPACT OF THE STUDY

Regardless the effect of the forage species, the use of LP as a microbial additive improved GP and kinetics and also increased OMD, TDS, MCP and enhanced the total in vitro ruminal VFAs production.

Molecular detection, phylogenetic analysis, and antibacterial performance of lactic acid bacteria isolated from traditional cheeses, North-West Iran

Lactic acid bacteria (LAB) are candidate probiotic bacteria that can provide health benefits when delivered via functional foods. The purpose of this study was to isolate and characterize LAB from traditional cheeses consumed in north-west regions of Iran. A number of sixty traditional cheeses samples were collected and initially screened as LAB using biochemical and molecular methods. A fragment of 1,540 bp in size of 16s rRNA gene was amplified from 70 bacterial isolates. Restriction fragment length polymorphism (RFLP) was employed to differentiate LAB isolates. LAB isolates generated three different RFLP patterns using HinfI restriction enzyme. Phylogenetic analysis revealed that LAB isolates belonged to three genera including Enterococcus, Lactobacillus, and Lactococcus. Most of the isolated LAB strains belonged to Enterococcus spp. The antimicrobial performance of eight LAB isolates with different RFLP patterns ranged from 6.72 to 14.00 mm. It was concluded that molecular characterization of LAB strains in traditional cheeses will enhance our understanding of traditional food microbiota and will help to find bacterial strains with probiotic potential with great benefit both in health and industry.