Effect of dietary modificatio of muscle long-chainN-3 fatty acid on plasma insulin and lipid metabolite, carcass traits, and fat deposition in lambs

In a previous study we showed that feeding fish meal significantly increased muscle long chain n-3 fatty acids (FA) and hot carcass weight. In this study we compared the effect of fish meal and fish oil on increasing muscle long-chain FA. We also investigated whether the increase in carcass weight was due to the effect of dietary enrichment of muscle long-chain n-3 FA on muscle membrane phospholipids and(or) to rumen by-pass protein provided by fish meal. Forty crossbred ([Merino x Border Leicester] x Poll Dorset) wether lambs between 26 and 33 kg BW were randomly assigned to one of five treatments: 1) basal diet of oaten:lucerne chaff (Basal); 2) Basal + fish meal (9% DM) = FM; 3) Basal + fish oil (1.5% DM) with protected sunflower meal (9% DM ) = FOSMP; 4) Basal + fish oil (1.5% DM) = FO; or 5) Basal + protected sunflower meal (10.5% DM) = SMP. Daily intake of ME (9.60 - 10.5 MJ ME/d) and CP (150 to 168 g/d) in all treatments was kept similar by varying the ratio of oaten:lucerne chaff and by feeding the animals at 90% ad libitum intake. Blood samples were collected at the start of the experiment and on the day (d 42) prior to slaughter. Lambs were then slaughtered at a commercial abattoir. At 24 h postmortem carcass traits were measured and longis-simus thoracis muscle taken for analysis of FA of phospholipid and triglyceride fractions. Lambs fed FO and FOSMP showed a marked increase in muscle longchain n-3 FA (P < 0.001) and a reduction in magnitude of the rise in insulin concentration (P < 0.001) after feeding compared with lambs fed Basal and SMP diets. Lambs in FM had a moderate increase (P < 0.001) in muscle long-chain n-3 FA content. Compared with Basal diet, both plasma total cholesterol (P < 0.02) and high-density lipoprotein cholesterol (P < 0.001) levels were greater in SMP and less in FO and FOSMP treat- ments. The i.m. fat content was reduced (P < 0.05) in FM and FO treatments, but carcass weight was increased only with fish meal (P < 0.03). Adding SMP to FO produced muscle with an intermediate level of i.m. fat, whereas muscle long-chain n-3 FA, i.m. fat, and insulin concentration were unchanged with SMP treatment. These results indicate that an increase in carcass weight in FM may be due to the supply of ruminally undegraded protein. They also suggest that fish oil along with fish meal can increase long-chain n-3 FA content in phospholipid of muscle membrane. This may be associated with reduced i.m. fat content and altered insulin action and lipoprotein metabolism.

Effects of dietary lipid type on muscle fatty acid composition, carcass leanness, and meat toughness in lambs.

Isonitrogenous amounts of two protein sources differing in rumen degradation rate and in lipid composition were fed to sheep with or without a rapidly fermentable cereal grain. The effects on intake, carcass leanness, and muscle fatty acid (FA) composition were examined. Thirty-eight crossbred wether lambs (9 mo, 35 to 48 kg) were allocated by stratified randomization to six treatment groups: 1) basal diet of alfalfa hay:oat hay (20:80) ad libitum = basal; 2) basal + lupin (358 g DM/d) = lupin; 3) basal + fish meal (168 g DM/d) = fish meal; 4) basal + barley (358 g DM/d) = barley; 5) basal + barley + lupin (179 + 179 g DM/d) = barley/lupin; or 6) basal + barley + fish meal (179 + 84 g DM/d) = barley/ fish meal. Lambs were fed individually. Dietary treatments were imposed for 8 wk, and the supplements were offered at 2-d intervals. Daily feed intake and weekly BW of lambs were recorded. At the end of the feeding period lambs were slaughtered after an overnight fast. Hot carcass weight (HCW) and fat depth (GR; total fat and muscle tissue depth at 12th rib, 110 mm from midline) were recorded. At 24 h postmortem samples of longissimus thoracis (LT) and longissimus lumborum (LL) muscles were taken from chilled (4 deg C) carcasses for the assessment of FA composition and meat tenderness, respectively. Lambs fed lupin or fish meal with or without barley had heavier slaughter weights (P < 0.004) and HCW (P < 0.001) than lambs fed basal or barley when initial BW was included as a covariate. The lupin diet also resulted in heavier carcasses (P < 0.05) than the fish meal or barley/fish meal diets. With GR as an indicator, fish meal and barley/ fish meal diets produced leaner carcasses (P < 0.01) than lupin and barley/lupin lambs. Long-chain n-3 FA content [20:5n-3 (P < 0.001), 22:5n-3 (P < 0.003), and 22:6n-3 (P < 0.001)] in the LT muscle were substantially higher with the fish meal and barley/fish meal diets, whereas muscle total n-6 FA was increased (P < 0.003) by lupin and barley/lupin compared with all other diets. Thus, increased muscle long-chain n-3 FA content occurred without an increase in fatness measured as GR, whereas increased muscle n-6 FA content was associated with an increase in carcass fatness. Under these circumstances, a reduction in carcass fatness had no effect on meat tenderness measured as Warner-Bratzler shear force.

Antimicrobial and toxicological studies of some metal complexes of 4-methylpiperazine-1-carbodithioate and phenanthroline mixed ligands

A few mixed ligand transition metal carbodithioate complexes of the general formula [M(4-MPipzcdt)_x(phen)_y]Y (M = Mn(II), Co(II), Zn(II); 4-MPipzcdt = 4-methylpiperazine-1-carbodithioate; phen = 1,10-phenanthroline; x = 1 and y = 2 when Y = Cl; x = 2 and y = 1 when Y = nil) were synthesized and screened for their antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa,Staphylococcus aureus and Enterococcusfaecalis by disk diffusion method. All the complexes exhibited prominent antimicrobial activity against tested pathogenic strains with the MIC values in the range <8-512 μgmL-1. The complexes [Mn(4-MPipzcdt)₂(phen)] and [Co(4-MPipzcdt)(phen)₂]Cl inhibited the growth of Candida albicans at a concentration as low as 8 µgmL^-1.The complexes were also evaluated for their toxicity towards human transformed rhabdomyosarcoma cells (RD cells). Moderate cell viability of the RD cells was exhibited against the metal complexes.

The effect of plant tissue and vaccine formulation on the oral immunogenicity of a model plant-made antigen in sheep

Antigen-specific antibody responses against a model antigen (the B subunit of the heat labile toxin of enterotoxigenic Escherichia coli, LTB) were studied in sheep following oral immunisation with plant-made and delivered vaccines. Delivery from a root-based vehicle resulted in antigen-specific immune responses in mucosal secretions of the abomasum and small intestine and mesenteric lymph nodes. Immune responses from the corresponding leaf-based vaccine were more robust and included stimulation of antigen-specific antibodies in mucosal secretions of the abomasum. These findings suggest that oral delivery of a plant bioencapsulated antigen can survive passage through the rumen to elicit mucosal and systemic immune responses in sheep. Moreover, the plant tissue used as the vaccine delivery vehicle affects the magnitude of these responses.