D.N. Kamra

Microbial status and rumen enzyme profile of crossbred calves fed on different microbial feed additives

Aims: To test various microbial cultures as cattle feed additives.

Effect of plant extracts on methanogenesis and microbial profile of the rumen of buffalo: a brief overview

Plants rich in secondary metabolites (saponins, tannins, essential oils, etc.) have antimicrobial activity which can be exploited for selective inhibition of a particular group of microbes in the rumen. We have screened a large number of plant extracts for their potential to inhibit methanogenesis and ciliate protozoa in an in vitro gas production test using buffalo rumen liquor as the inoculum. Out of 93 plant extracts tested, 11 inhibited in vitro methanogenesis to the extent of 25–50% and nine plant extracts inhibited methanogenesis more than 50%. Among 20 extracts exhibiting antimethanogenic activity, nine were ethanol extracts, 10 were methanol extracts and only one was a water extract. Some of these plant extracts inhibited ciliate protozoa as tested by microscopic examination and 14C-labelled radioisotopic technique, but the protozoa inhibition was not correlated with methane inhibition, indicating that the methanogens sensitive to plant secondary metabolites may or may not be having any symbiotic relationship with ciliate protozoa. Methane inhibition was accompanied by a drastic fall in the number of methanogens as determined by real time PCR. Plants that appeared to have some potential as feed additives to control methanogenesis by the ruminants are: (i) seed pulp of Sapindus mukorossi (rich in saponins) and Terminalia chebula (rich in tannins); (ii) leaves of Populus deltoides, Mangifera indica and Psidium guajava (rich in tannins and essential oils); and (iii) flower buds of Syzygium aromaticum and bulb of Allium sativum (rich in essential oils). Some of the plants reported in literature exhibiting antimethanogenic activity include Equisetum arvense, Lotus corniculatus, Rheum palmatum, Salvia officinalis, Sapindus saponaria, Uncaria gambir and Yucca schidigera.

Diurnal variation in ciliate protozoa in the rumen of black buck (Antilope cervicapra) fed green forage

The protozoa in the rumen of a black buck were a B‐type population with numbers varying between 0·31 and 0·61 times 106cells/ml rumen liquor, when the animal was fed either vegetative green oat or third cut berseem. The total protozoa, total holotrichs, Dasytricha, total spirotrichs and small spirotrichs were significantly higher (P < 0·01) on berseem feeding than those on oat feeding, while the numbers of Isotricha and large spirotrichs were unaffected by change of diet. Numerically the most important group of protozoa was small spirotrichs (74·4–75·6% of total population) which accounted for only 9·85–13·61% of protozoal cell mass in the rumen.

Effects of extracts of spices on rumen methanogenesis, enzyme activities and fermentation of feeds in vitro

BACKGROUND An experiment was conducted to study the effects of boiling water, methanol and ethanol extracts (0, 0.25 and 0.50 mL) of seeds of Foeniculum vulgare (fennel), flower buds of Syzygium aromaticum (clove), bulbs of Allium sativum (garlic), bulbs of Allium cepa (onion) and roots of Zingiber officinalis (ginger) on rumen methanogenesis, fibrolytic enzyme activities and fermentation characteristics in vitro. RESULTS Ethanol and methanol extracts of fennel, clove and garlic at 0.50 mL and clove at 0.25 mL inhibited (P < 0.05) methane production. Carboxymethylcellulase activity was reduced (P < 0.05) by ethanol and methanol extracts (0.50 mL) of fennel and clove (0.25 and 0.50 mL). The extracts of clove reduced (0.25 and 0.50 mL) xylanase and acetylesterase activities, and the fennel extract (0.50 mL) reduced (P < 0.05) xylanase activity. However, the extracts of garlic (0.50 mL) increased (P < 0.05) acetylesterase activity. Concentrations of volatile fatty acids were reduced (P < 0.05) by the extracts of garlic and onion. The extracts of garlic caused a decrease (P < 0.05) in acetate:propionate ratio (A:P) at 0.50 mL, whereas A:P was increased (P < 0.05) by the inclusion of 0.50 mL extracts of clove. Methanol and ethanol extracts of clove decreased (P < 0.05) in vitro organic matter degradability. Extracts (0.50 mL) of clove decreased (P < 0.05) the numbers of total protozoa, small entodiniomorphs and holotrichs, whereas extracts of onion, ginger and garlic enhanced (P < 0.05) protozoal numbers (both entodiniomorphs and holotrichs). CONCLUSION Ethanol and methanol extracts of fennel and garlic have potential to inhibit rumen methanogenesis without adversely affecting rumen fermentation.

Selection of Saccharomyces cerevisiae strains for use as a microbial feed additive

Saccharomyces cerevisiae ITCCF 2094, NCIM 3052, 1031, 1032, NCDC 42, 45, 47, 49 and 50 were screened for their tolerance to pH 2·0–7·0, various concentrations (0·00, 0·10, 0·25 0·50 and 1·0%) of a mixture of acetic, propionic and butyric acids (70:20:10), and bile salts (0·00, 0·30, 0·60 and 0·90%). Low pH (2·0–4·0) and addition of organic acids or bile salts in the medium inhibited the growth of all the strains tested, but the percentage of inhibition was variable in the different strains of yeast. Two of the strains showing maximum tolerance, 42 and 49, were further tested for in vitro dry matter degradability (IVDMD) using green berseem, wheat straw and oat hay as substrates. Saccharomyces cerevisiae 49 enhanced the IVDMD of berseem and wheat straw whereas S. cerevisiae 42 was ineffective. Based on the results of the present experiment, S. cerevisiae NCDC 49 can be considered as the best strain which might tolerate the adverse conditions in the gastrointestinal tract when used as a live microbial feed supplement in the diet of the animals.

Effect of phenolic monomers on biomass and hydrolytic enzyme activities of an anaerobic fungus isolated from wild nil gai (Baselophus tragocamelus)

Aims: To test the anaerobic fungus, Piromyces sp. FNG5, for its tolerance to phenolic monomers released in the rumen by degradation of lignocellulosic poor‐quality feeds.

Bioconversion of sugarcane bagasse with white rot fungi

SummaryFour cultures of white rot fungi were screened for their ability to degrade lignin and carbohydrates of sugarcane bagasse and their effect on changes ininvitro digestibility.Polyporushirsutus534 degraded maximum lignin and carbohydrates accompanied with the highest increase in digestibility, but increase in nutrient availability was maximum withPleurotussajorcaju (Z-6) due to lower dry matter loss during the process of fungal treatment. All the fungi tested exceptPolyporuscaperatus Berk. degraded lignin more selectively than the other components of sugarcane bagasse.

Effect of Sapindus mukorossi Extracts on in vitro Methanogenesis and Fermentation Characteristics in Buffalo Rumen Liquor

Abstract Agarwal, N., Kamra, D.N., Chaudhary, L.C. and Patra, A.K. 2006. Effect of Sapindus mukorossi extracts on in vitro methanogenesis and fermentation characteristics in buffalo rumen liquor. J. Appl. Anim. Res., 30: 1–4. The berries of Sapindus mukorossi (soap nut) extracted in water, methanol and ethanol were tested for their effects on methanogenesis and fermentation of feed with buffalo rumen liquor in in vitro gas production test. The degression in methane and gas production was 96% and 39.4%, 20% and 11.5%, 22.7% and 0% with ethanol, water and methanol extracts, respectively, as compared to respective controls. The extracts also exhibited antiprotozoal activity resulting in 70–90% lesser protozoa count in the treated samples. The proportion of acetate was lower (P<0.05) and that of propionate higher (P<0.05) resulting in a decrease in acetate/propionate ratio with all the three extracts tested. The pH of incubation medium containing extract was significantly lower as compared with the medium without any extract. There was a significant depression in in vitro dry matter degradability of feed with all the three extracts. The data indicated that soapnut extracts appear to have a potential to be used as antimethanogenic and antiprotozoal agents.

Biodegradation of tannins in oak (Quercus incana) leaves by Sporotrichum pulverulentum

Fermentation of oak leaves with Sporotrichum pulverulentum decreased the contents of total phenols and condensed tannins by 58 and 66% respectively in 10 d. The protein precipitation capacity decreased by 65%. Further increase of fermentation time up to 40 d did not increase substantially, the tannin degradation. Following fermentation, neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin decreased by 12–16%, 8–10%, 31–51%, 0.3‐3% and 14–15% respectively. The loss in dry matter was from 17–21%. The in sacco dry matter digestibility of the fermented leaves was 17% compared to 27% for the unfermented leaves.

Diurnal variations in the activities of hydrolytic enzymes in different fractions of rumen contents of Murrah buffalo.

Abstract Agarwal, N., Agarwal, I., Kamra, D.N. and Chaudhary, L.C. 2000. Diurnal variations in the activities of hydrolytic enzymes in different fractions of rumen contents of Murrah buffalo. J. Appl. Anim. Res. 18: 73–80. The hydrolytic enzymes like carboxymethylcellulase, α-amylase, xylanase, microcrystalline cellulose and filter paper degrading activities were estimated in various fractions of rumen contents of Murrah buffalo. About 80–92% of the enzyme activities were associated with the particulate material, while only a negligible portion (1–4%) was present as extracellular fraction in the liquid portion of rumen contents. Rest of the activities (8–15%) were associated with freely suspended microbial cells in the liquid portion of the rumen contents. Maximum activities of carboxymethylcellulase, α-amylase, xylanase and micro-crystalline cellulase were observed at 2h post feeding while in the case of filter paper degrading activity, there was no difference in the activities in the first 4 hours of offering feed to the animals.