Effects of high protein levels in concentrate feed during the early fattening stage on physico-chemical composition and sensory characteristics of M. longissimus in Japanese Black heifers

The effects that high levels of protein in concentrate feed has during the early fattening stage on physico-chemical composition and sensory characteristics of M. longissimus in Japanese Black heifers were investigated. Four sets (8 head) of identical twins of Japanese Black heifers were divided into two groups: a group fed high levels of protein in concentrate feed in the early fattening stage (HCP); and a control group. Moisture, fat, protein, cooking loss, Warner-Bratzler shear force and fatty acid composition of M. longissimus were similar in both groups. Levels of free amino acid (FAA), aspartic acid, glutamine, taurine and histidine were lower in the HCP group than in the control group ( P  < 0.05). Levels of glutamic acid, serine, asparagine, threonine and total FAA in the HCP group tended to be lower than in the control group ( P  < 0.1). There were no significant differences between the sensory characteristics (juiciness, tenderness, fattiness, flavor and overall acceptability) of the two groups. These results suggest that the use of high levels of protein in concentrate feed during the early fattening stage does not affect the sensory characteristics of Japanese Black beef, but does alter the FAA content.     

Detection and identification of rumen bacteria constituting a fibrolytic consortium dominated by Fibrobacter succinogenes

A fibrolytic consortium, dominated by the rumen cellulolytic bacterium Fibrobacter succinogenes, was artificially constructed on hay stems to detect and identify rumen bacteria that can potentially interact with F. succinogenes . Consortium-bacterial members were determined by DGGE and sequencing analysis targeted bacterial 16S rDNA. An artificial consortium was formed in a 2-step incubation of hay stems; the first step with group 1, 2 or 3 F. succinogenes strains, the second step with rumen fluid. After consortium formation, morphologically different bacteria were observed in association with F. succinogenes . DGGE exhibited more than 30 bands, the pattern of which depended on the F. succinogenes group. Sequencing suggested that Butyrivibrio fibrisolvens, Pseudobutyrivibrio ruminis , Clostridium sp., F. succinogenes group 2, Prevotella ruminicola and unclassified Bacteroides were prominent in the group 1 consortium and that Treponema bryantii , B. fibrisolvens , Acinetobacter sp, and Wolinella succinogenes were prominent in the group 2 consortium. However, in the group 3 consortium, F. succinogenes -like bacteria were microscopically undetectable, whereas cellulolytic Ruminococcus albus and F. succinogenes group 1 were prominent, suggesting that the group 3 cannot be a core member of this consortium. This study is the first attempt to identify bacterial members of a fibrolytic consortium dominated by a specific bacterium.     

Interaction of rumen bacteria as assumed by colonization patterns on untreated and alkali‐treated rice straw

Colonization patterns of representative rumen bacteria were compared between untreated rice straw (UTS) and sodium hydroxide‐treated rice straw (SHTS). UTS and SHTS were incubated in the rumen of sheep for 10 min, 1, 2, 6, 12, 24, 48 and 96 h using the nylon bag method. The population sizes of 13 representative bacterial species or groups were quantified by real‐time PCR. The total bacterial population size (abundance) was similar in both UTS and SHTS. Fibrobacter succinogenes showed a higher population size compared to other fibrolytic species and was detected at a higher level in SHTS (3.7%) than in UTS (2.6%). Ruminococcus albus and Ruminococcus flavefaciens were also detected at higher levels in SHTS (0.15% and 0.29%) than in UTS (0.03% and 0.18%). Population sizes of non‐fibrolytic species, such as Selenomonas ruminantium, Anaerovibrio lipolytica and Succinivibrio dextrinosolvens were higher in UTS than in SHTS. Coefficient of determination (r²) on population changes between bacterial species or groups were higher in UTS than in SHTS, suggesting the necessity of stronger bacterial interactions for UTS digestion. Therefore, not only colonization of fibrolytic species, but also synergistic interactions between different bacterial species may be key to the ruminal digestion of rice straw.     

Development of immune assay system for both CpG and non-CpG DNA from lactic acid bacteria using a transfectant of swine Toll-like receptor 9

Bacterial DNA is expected to be a potent immune stimulating agent to Toll‐like receptor (TLR) 9 expressed cells such as macrophages, monocytes, B lymphocytes, NK cells and dendritic cells. In the present study, we constructed a transfectant of swine TLR9 with mammalian cells. We demonstrated that the transfectant, recognizing both CpG and non‐CpG oligonucleotides from lactic acid bacteria, induced NF‐κB activation by gene reporter assay. These findings indicate that the swine TLR9 transfectant will be highly useful for the screening of immunostimulatory DNA from lactic acid bacteria.     

A morphological study of the thyroid gland in Risso's Dolphin,Grampus griseus

To accumulate histological information of cetaceans and basic information about metabolic systems of marine mammals, the thyroid gland of Risso's dolphins was examined by gross anatomical and light and electron microscopic observations. Gross anatomically, right and left lobes of the thyroid were not clearly discriminated, and no isthmus was observed. By light microscopy, irregular or oval follicular lumens were seen, and surrounded by follicular epithelial cells. By electron microscopy, the rough endoplasmic reticulum (rER) was seen adjacently to mitochondria at the basal and lateral regions of the follicular epithelial cells. RERs at the basal side of the cells sometimes contained flocculent material with the same electron density as the follicular lumen component. Microvilli were poorly developed at the apical surface of the cells. In the apical regions of the cells, there were typical Golgi complexes, multivesicular bodies, and granules with various size and electron density. The parafollicular cells were recognized among the follicular epithelial cells and in the interstitial regions but never protruded into the follicular lumen. These cells were present singly and/or formed clusters among the follicular epithelial cells, and often located adjacent to capillaries. They were obviously discriminated from follicular epithelial cells by higher electron density of their granules. In their cytoplasm, well-developed rERs, primary lysosomes, secondary lysosomes, multivesicular bodies, and phagosomes were recognized.     

Fiber digestion in various segments of the hindgut of horses fed grass hay or silage

We studied in vivo fiber digestibility and fermentation parameters such as volatile fatty acid concentration and in vitro degradation in each segment of hindgut of horses fed timothy hay or silage made from the same sward. Six Thoroughbred horses were fed timothy hay or silage in equal amounts (1.6% of bodyweight per day, bodyweight mean 572 kg) every 3 h per day, then slaughtered. There were no differences between hay and silage in the concentration of the total volatile fatty acids, the apparent digestibility of dry matter, organic matter, and fiber, and in vitro neutral detergent fiber (NDF) disappearance rate in each segment. The total volatile fatty acid concentration and the apparent digestibility of dry and organic matter and fiber differed ( P  < 0.01) depending on the digestive segments. Both for hay and silage, the concentration of total volatile fatty acids in the digesta liquid phase largely increased ( P  < 0.01) from the cecum to the right ventral colon, and kept a constant value from the right ventral colon to the right dorsal colon, and then decreased from the right dorsal colon to the small colon. For dry and organic matter and fiber components, the apparent digestibility changed in the same manner from former to hinder segments of the hindgut. Regardless of diet, dry and organic matter and fiber components showed lower values in the cecum and the right ventral colon and increased ( P  < 0.01) largely from the right ventral colon to the left dorsal colon, then kept constant values in segments to the rear of left dorsal colon. There were no differences in in vitro NDF disappearance among cecum, ventral colon and dorsal colon.