Junichi Takahashi

Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.

The source and composition of dissolved organic matter (DOM) are important drivers of its biogeochemical role in aquatic environments. Different land use types may alter DOM amount and composition in freshwaters. Here, water samples were collected from the outlets of 16 subcatchments within mixed land use patterns in the South Tiaoxi River in Eastern China. Dissolved organic carbon (DOC), DOM absorption coefficient (α₃₅₀), and fluorescence spectrum were measured. These 16 subcatchments were grouped into four clusters with different land use features: natural forest land, planted forest land (Phyllostachys praecox, a bamboo species), cropland, and residential land. Two humic-like and two protein-like fluorescent components were identified using parallel factor analysis (PARAFAC). DOC concentrations were the lowest in natural forest land dominated subcatchments as compared to other land uses with intensive anthropogenic activities, so did α₃₅₀ and fluorescent intensities of different components. Protein-like fluorescence was more pronounced for the subcatchments dominated by residential land, while terrestrial humic-like fluorescence was the most abundant component for the subcatchments dominated by the other three land use types. The relationships between the percentage of cropland and that of fluorescence fraction appear to be a threshold response, indicating that effects on DOM composition varied with agricultural activity patterns. The reservoir would have a positive effect on DOM amount and the percentage of protein-like fluorescence associated with autochthonous activities. This study in general shows the impact of anthropogenic land use patterns on the amount and composition of DOM in headwater streams, which may affect ecosystem function and health of aquatic environments.

Prophylactic Modulation of Methane and Nitrous Oxide Emitted from Ruminants Livestock for Sustainable Animal Agriculture (REVIEW)

The abatement of methane emission from ruminants is an important global issue due to its contribution to greenhouse gas with carbon dioxide. Methane is generated in the rumen by methanogens (archaea) that utilize metabolic hydrogen (H 2) to reduce carbon dioxide, and is a significant electron sink in the rumen ecosystem. Therefore, the competition for hydrogen used for methanogenesis with alternative reductions of rumen microbes should be an effective option to reduce rumen methanogenesis. Some methanogens parasitically survive on the surface of ciliate protozoa, so that defaunation or decrease in protozoa number might contribute to abate methanogenesis. The most important issue for mitigation of rumen methanogenesis with manipulators is to secure safety for animals and their products and the environment. In this respect, prophylactic effects of probiotics, prebiotics and miscellaneous compounds to mitigate rumen methanogenesis have been developed instead of antibiotics, ionophores such as monensin, and lasalocid in Japan. Nitrate suppresses rumen methanogenesis by its reducing reaction in the rumen. However, excess intake of nitrate causes intoxication due to nitrite accumulation, which induces methemoglobinemia. The nitrite accumulation is attributed to a relatively higher rate of nitrate reduction to nitrite than nitrite to ammonia via nitroxyl and hydroxylamine. The in vitro and in vivo trials have been conducted to clarify the prophylactic effects of L-cysteine, some strains of lactic acid bacteria and yeast and/or β1-4 galactooligosaccharide on nitrate-nitrite intoxication and methanogenesis. The administration of nitrate with β1-4 galacto-oligosaccharide, Candida kefyr, and Lactococcus lactis subsp. lactis were suggested to possibly control rumen methanogenesis and prevent nitrite formation in the rumen. For prebiotics, nisin which is a bacteriocin produced by Lactococcus lactis subsp. lactis has been demonstrated to abate rumen methanogenesis in the same manner as monensin. A protein resistant anti-microbe (PRA) has been isolated from Lactobacillus plantarum as a manipulator to mitigate rumen methanogenesis. Recently, hydrogen peroxide was identified as a part of the manipulating effect of PRA on rumen methanogenesis. The suppressing effects of secondary metabolites from plants such as saponin and tannin on rumen methanogenesis have been examined. Especially, yucca schidigera extract, sarsaponin (steroidal glycosides), can suppress rumen methanogenesis thereby improving protein utilization efficiency. The cashew nutshell liquid (CNSL), or cashew shell oil, which is a natural resin found in the honeycomb structure of the cashew nutshell has been found to mitigate rumen methanogenesis. In an attempt to seek manipulators in the section on methane belching from ruminants, the arrangement of an inventory of mitigation technologies available for the Clean Development Mechanism (CDM) and Joint Implementation (JI) in the Kyoto mechanism has been advancing to target ruminant livestock in Asian and Pacific regions.

Effects of protease-resistant antimicrobial substances (PRA) produced by Lactobacillus plantarum and Leuconostoc citreum on rumen methanogenesis were examined using the in vitro continuous methane quantification system. Four different strains of lactic acid bacteria, i) Lactococcus lactis ATCC19435 (Control, non-antibacterial substances), ii) Lactococcus lactis NCIMB702054 (Nisin-Z), iii) Lactobacillus plantarum TUA1490L (PRA-1), and iv) Leuconostoc citreum JCM9698 (PRA-2) were individually cultured in GYEKP medium. An 80 ml aliquot of each supernatant was inoculated into phosphate-buffered rumen fluid. PRA-1 remarkably decreased cumulative methane production, though propionate, butyrate and ammonia N decreased. For PRA-2, there were no effects on CH 4 and CO 2 production and fermentation characteristics in mixed rumen cultures. The results suggested that PRA-1 reduced the number of methanogens or inhibited utilization of hydrogen in rumen fermentation.

The objective of the study was to evaluate effects of Quillaja saponaria (QS) with or without Yucca schidigera extract (YS) on in vitro ruminal fermentation and methanogenesis. The culture media consisted of 400 mL of strained rumen fluid collected from two non‐lactating Holstein cows and 400 mL of artificial saliva. The culture media was anaerobically incubated with 10 g of a mixture of concentrate and oat hay (1:1, w/w) at 39°C for 24 h. The treatments were arranged as 2 × 3 factorial design experiment consisting of three levels of QS (0, 2 or 4 mL/L) and two levels of YS (0 or 2 mL/L). Treatment interactions between QS and YS were observed for pH and ammonia N concentration. CH₄ production was not modified by addition of QS but decreased (P < 0.05) when added with YS. Addition of QS with YS increased (P < 0.05) propionate concentrations. Protozoa numbers were decreased (P < 0.05) by QS addition alone or with YS. Results show that QS and YS exhibited strong antiprotozoal effects and combinations of both plant extracts may have potential as safe manipulators of ruminal fermentation.

The effects of two kinds ofEscherichia coli(E. coli) strain, wild-typeE. coliW3110 andE. colinir-Ptac, which has enhanced NO₂reduction activity, on oral CH₄emission and NO₃toxicity in NO₃-treated sheep were assessed in a respiratory hood system in a 4×6 Youden square design. NO₃(1·3g NaNO₃/kg^0·75body weight) and/orE. colistrains were delivered into the rumen through a fistula as a single dose 30min after the morning meal.Escherichia colicells were inoculated for sheep to provide an initialE. colicell density of optical density at 660nm of 2, which corresponded to 2×10¹⁰cells/ml. The six treatments consisted of saline,E. coliW3110,E. colinir-Ptac, NO₃, NO₃plusE. coliW3110, and NO₃plusE. colinir-Ptac. CH₄emission from sheep was reduced by the inoculation ofE. coliW3110 orE. colinir-Ptac by 6% and 12%, respectively. NO₃markedly inhibited CH₄emission from sheep. Compared with sheep given NO₃alone, the inoculation ofE. coliW3110 to NO₃-infused sheep lessened ruminal and plasma toxic NO₂accumulation and blood methaemoglobin production, while keeping ruminal methanogenesis low. Ruminal and plasma toxic NO₂accumulation and blood methaemoglobin production in sheep were unaffected by the inoculation ofE. colinir-Ptac. These results suggest that ruminal methanogenesis may be reduced by the inoculation ofE. coliW3110 orE. colinir-Ptac. The inoculation ofE. coliW3110 may abate NO₃toxicity when NO₃is used to inhibit CH₄emission from ruminants.