Effect of dietary energy source on in vitro substrate utilization and insulin sensitivity of muscle and adipose tissues of Angus and Wagyu steers

Angus (n = 8; 210 kg of BW) and 7/8 Wagyu (n = 8; 174 kg of BW) steers were used to evaluate the effects of dietary energy source on muscle and adipose tissue metabolism and insulin sensitivity. Steers were assigned to either a grain-based (corn) or hay-based (hay) diet and fed to similar final BW. At slaughter, LM and s.c. and i.m. adipose tissue samples were collected. Portions of the LM and adipose tissues were placed immediately in liquid N for later measurement of glycolytic intermediates. Fresh LM and s.c. and i.m. adipose tissues were incubated with [U-(14)C]glucose to assess glucose metabolism in vitro. All in vitro measures were in the presence of 0 or 500 ng/mL of insulin. Also, s.c. and i.m. adipose tissues were incubated with [1-(14)C]acetate to quantify lipid synthesis in vitro. Glucose-6-phosphate and fructose-6-phosphate concentrations were 12.6- and 2.4-fold greater in muscle than in s.c. and i.m. adipose tissues, respectively. Diet did not affect acetate incorporation into fatty acids (P = 0.86). Insulin did not increase conversion of glucose to CO(2), lactate, or total lipid in steers fed hay but caused an increase (per cell) of 97 to 110% in glucose conversion to CO(2), 46 to 54% in glucose conversion to lactate, and 65 to 160% in glucose conversion to total lipid content in adipose tissue from steers fed corn. On a per-cell basis, s.c. adipose tissue had 37% greater glucose oxidation than i.m. adipose (P = 0.04) and 290% greater acetate incorporation into fatty acids than i.m. adipose (P = 0.04). Insulin addition to s.c. adipose tissue from corn-fed steers failed to stimulate glucose incorporation into fatty acids, but exposing i.m. adipose tissue from corn-fed steers to insulin resulted in a 165% increase in glucose incorporation into fatty acids. These results suggest that feeding hay limited both glucose supply and tissue capacity to increase glucose utilization in response to insulin without altering acetate conversion to fatty acids. Because s.c. adipose tissue consistently utilized more acetate and oxidized more glucose than did i.m. adipose, these results suggest that hay-based diets may alter i.m. adipose tissue metabolism with less effect on s.c. adipose tissue.     

Tasco supplementation: effects on carcass characteristics, sensory attributes, and retail display shelf-life

Two hundred crossbred cattle (Bos indicus x Bos taurus) were supplemented with 2% Tasco (Ascophyllum nodosum) in a commercial finishing facility to evaluate marbling score, USDA quality grade, sensory traits, and retail display shelf life. Treatment animals (n = 100) received a steam-rolled corn (Zea mays)-based diet containing 2% Tasco meal (DM basis), for 14 d beginning at d 45 of the finishing period and again 14 d before slaughter. Control animals (n = 100) received a steam-rolled corn (Zea mays)-based diet without Tasco at identical feeding periods. Carcasses from Tasco-fed cattle exhibited greater marbling scores (P = 0.003) than controls. There were no treatment effects (P > 0.05) on sensory, shear, or purge attributes of striploin or inside round steaks with the exception of inside round steaks from Tasco animals having a greater initial tenderness (P = 0.03) and lower off-flavor score (P = 0.002) than control steaks. The LM samples from Tasco-fed cattle had a greater percentage of ether extractable fat (P = 0.001) and lower percentage of protein (P = 0.001) than controls. Inside round samples from treated animals exhibited a greater percentage of moisture (P = 0.03) than control steaks. Visual lean color of striploin steaks was not affected by Tasco supplementation (P = 0.26); however, steaks from Tasco-treated animals were more uniform and had less discoloration and browning than those from controls (P = 0.005, 0.04, and 0.05, respectively). Inside round visual scores and instrument values reflected similar treatment responses (P < 0.05), with a majority of the effects on muscle redness (CIE a*, hue angle) and measures of discoloration. Tasco steaks were generally more red and less discolored during extended postmortem aging and retail exposure (P < 0.05). The results from this study indicate that short-term supplementation of 2% Tasco meal in feedlot cattle increases carcass quality and prolonged retail shelf life.     

Distribution and Activity of Fatty Acid Amide Hydralase (FAAH) in the Gastrointestinal Neurons of Mouse

The endocannabinoid anandamide may regulate intestinal motility through activation of CB1 receptors. Anandamide is then inactivated by fatty acid amide hydrolase (FAAH), a membrane bound enzyme. Under pathological conditions, inactivation of such enzymatic activity may lead to inhibition of the intestinal motility. Here, preliminary reports on the distribution of Fatty Acid Amide Hydrolase (FAAH) immunoreactivity in the mouse gastrointestinal neurons, and the pharmacological effects of N‐arachidonoylserotonin (AA‐5HT), a selective inhibitor of FAAH, are reported. FAAH was revealed by an indirect immunofluorescence. Laminar preparations containing the myenteric or the submucous plexus adhered, were peeled off after the whole gut wall had been stretched out and fixed in 4% paraformaldehyde. They were subsequently incubated with a polyclonal anti‐serum directed against a region near the N‐terminus of the human FAAH and revealed by a FITC‐conjugated goat anti‐rabbit secondary anti‐serum. FAAH‐immunoreactive neurons were observed within the myenteric ganglia throughout the GIT. The positive nerve cells varied in size and density of immunoreactivity. Stomach and large intestine showed the highest neuronal density. AA‐5HT significantly reduced both gastric emptying and gastrointestinal tract transit. Such inhibitory effect was reduced by the C1 receptor antagonist SR141716A. Both morphological and pharmacological results suggest that FAAH may play a critical role in controlling gut anandamide levels.     

Monoclonal antibodies identify phenotypically and functionally distinct cell types in the bovine lymphoid system

Monoclonal antibodies were produced against bovine lymphoid cells. The reactivities of the antibodies for membrane determinants were examined on both cell suspensions and cryostat tissue sections prepared from bovine blood, thymus, spleen and lymph nodes. The antibodies were putatively grouped into sets which reacted with monomorphic and polymorphic determinants associated with bovine class I and class II major histocompatibility complex (MHC) antigens (MAbs P12 and P3, and R1 and P2 respectively), or associated with differentiation antigens expressed on T cells and monocytes (MAb P5) or exclusively on monocytes (MAb P8). The antibodies were used to identify the surface phenotypes of cells which stimulate (R1+ P5+ P8+) and proliferate (R1- P5+ P8-) in the bovine mixed leukocyte cultures, and cells which proliferate in response to the mitogen, concanavalin A (R1- P5+).     

The vaginal mucus agglutination test in the diagnosis of bovine brucellosis

Of 1140 vaginal mucus agglutination tests (VMAT) on specimens obtained in 1971-72 from 663 dairy cows in seven herds infected with brucellosis, 97 were positive. When the VMAT was positive one or more serological tests were also positive. Of the 97 corresponding serum agglutination tests 80 sera had titres of more than 533 international units. Only 69.8 per cent of VMAT from serologically positive cows were positive. No evidence was found of non-specific agglutinins in vaginal mucus and positive VMAT reactions appeared to be specific for field infection. Three cows showed evidence of local agglutinins in the vagina. Hence herd testing by VMAT has no advantage over tests of blood serum but the test could be an aid in establishing whether individual cattle are infected.     

Immunomodulation with killed Propionibacterium acnes in guinea pigs simultaneously vaccinated with Brucella abortus strain 19

Immunomodulation with killed Propionibacterium acnes was attempted in guinea pigs simultaneously vaccinated with Brucella abortus strain 19. Two groups, each comprised of 9 guinea pigs, were injected by different routes (s.c. and or i.v.) with 1.4 mg of P. acnes and 5 X 10(8) CFU of B. abortus, S-19, while 3 other groups each received either P. acnes, B. abortus S-19, or saline (s.c.). The antibody titers to B. abortus measured at 6, 10 and 14 weeks after vaccination indicated no significant (P less than 0.01) response in the 2 groups immunopotentiated with P. acnes concurrent with B. abortus S-19 vaccination. The delayed hypersensitivity response to 3 Brucella antigens conducted 8 weeks after immunization did not show a significant difference between the B. abortus S-19 vaccinated group compared with the 2 groups immunopotentiated and vaccinated. However, the proliferative response of lymphocytes to the B. abortus soluble antigen diluted 1:100 indicated significantly enhanced blastogenesis in the (s.c.) immunopotentiated and immunized guinea pigs compared with the B. abortus S-19 vaccinated group. A slightly enhanced response was also observed in the group immunopotentiated (i.v.) and vaccinated (s.c.). The guinea pigs were challenged with B. abortus strain 2308 and necropsied 4 weeks later. The mean splenic CFU of the Brucella in the group immunopotentiated (i.v.) and vaccinated (s.c.) was significantly decreased when compared with the guinea pigs vaccinated with B. abortus S-19 alone. These findings indicated that P. acnes administered simultaneously with B. abortus S-19 vaccine was able to augment the immune response in guinea pigs. Immunomodulation as evidenced by enhanced clearance of B. abortus from the spleens of immunopotentiated animals was presumably brought about by activated macrophages or a T-cell mediated cytolytic mechanism or both.