BACKGROUND: Plasma lipoprotein profile is one of the effective mechanisms in testicular tissue development and spermatogenesis process in roosters. OBJECTIVES: The present study was conducted to investigate the effect of dietary supplementation of l-carnitine during pre-pubertal period on testicular histology, spermatogenesis indexes and plasma lipoproteins of immature cockerels METHODS: A total of twelve Ross broiler breeder males (12 weeks) for 22 weeks in a completely randomized design with two treatments (0, and 250 mg/kg of L-carnitine in the diet) and six replications were used. Feeding program, and photoperiod regimen was performed based on ROSS 308 management handbook. To achieve the objectives of the study, at the age of 34 weeks, four birds were randomly selected from each treatment and after collecting blood samples from the veins under the wings, the birds were slaughtered. Finally, plasma cholesterol, LDL and HDL concentrations using a commercial kit and testicular parameters (number of seminiferous tubules, number of Sertoli cells, height of epithelium seminiferous tubules, seminiferous tubules diameter, spermatogenesis index, and tubular differentiation index) after preparation of 5-μm paraffin sections, were analyzed by SAS software. RESULTS: The results showed that the number of seminiferous tubules, and the number of Sertoli cells were significantly affected by l-carnitine (p < /em><0.05). L-carnitine supplementation in the diet of immature cockerels before sexual maturity significantly increased the spermatogenesis index (p < /em><0.003) and tubular differentiation index (p < /em><0.02). HDL levels were significantly affected by l-carnitine supplementation (p < /em><0.007). There was a significant tendency in LDL concentration (p < /em>=0.09) and LDL/HDL ratio (p < /em>=0.059) between treatments, but no significant differences were observed in cholesterol concentration between treatments. CONCLUSIONS: According to the results of this study, feeding immature cockerels before sexual maturity with 250 mg l-carnitine improves testicular tissue development and spermatogenesis process.

Ethionine, an analogue of methionine, induces fatty liver in rats by inhibiting protein synthesis, including that of apolipoproteins in liver. Ethionine was administered to cows to elucidate the participation in fatty liver development of impaired triglyceride secretion from liver attributable to decreased apolipoprotein synthesis. The administration resulted in a significant increase of liver triglyceride contents. Several apolipoproteins were found to have decreased concentrations. In particular, apolipoprotein B-100 in very low-density (0.95 to 1.006 g/ml) lipoprotein and in low-density (1.006 to 1.063 g/ml) lipoprotein fractions was greatly reduced. The decreases of apolipoprotein B-100 concentrations in the 2 lipoprotein fractions were at least partly correlated to the decreased triglyceride concentrations in the respective fractions. Decreased concentrations of apolipoprotein A-I in high-density (1.063 to 1.210 g/ml) lipoprotein were also observed, although not as distinctly as with apolipoprotein B-100. Total cholesterol and phospholipid concentrations in low- and high-density lipoprotein fractions were decreased. The decrease in cholesterol was attributed to reduced concentrations of cholesteryl esters. It was suggested that the impaired lipid secretion from liver attributable to the decreased apolipoprotein concentrations has a role in ethionine-induced fatty liver of cows.

The Streptococcus suis 103 gene product is an immunogenic and protective lipoprotein that is a component of an ATP-binding cassette transporter implicated in zinc uptake. Belonging to the same transcriptional unit and downstream of the 103 gene is a gene that encodes a homologue of the pneumococcal histidine triad (Pht) protein Pht309. In an intraperitoneal mouse model the virulence of a mutant lacking the 103 gene was more than 50 times lower than that of the wild-type (WT) parent strain, S. suis serotype 2 strain P1/7. In addition, the immunogenicity of this mutant was dramatically decreased. In striking contrast, the virulence and immunogenicity of a P1/7 mutant lacking the Pht309 gene were similar to those of the parent strain. These results demonstrate that the 103 lipoprotein is strongly involved in S. suis virulence and support the hypothesis that this lipoprotein might be an excellent candidate for vaccines aiming to achieve broad protection against streptococci.

Methods available for measurement of plasma lipoprotein-cholesterol concentrations and activities of lipoprotein lipase, hepatic lipase, lecithin:cholesterol acyl transferase (LCAT), and cholesteryl ester transfer protein were adapted for use in cats. A combined ultracentrifugation/precipitation procedure was used to isolate very low-density lipoproteins (VLDL), then to separate low-density lipoproteins (LDL) from high-density lipoproteins (HDL). The reagent used, 92 mM heparin-manganese chloride, provided complete precipitation of LDL with only trace and insignificant contamination by HDL. Efforts to selectively measure lipoprotein lipase activity in plasma, collected after IV injection of heparin, by inhibiting hepatic lipase with sodium dodecyl sulfate were unsuccessful, and the activity of this enzyme was calculated as the difference between total and hepatic lipase activities. The latter was measured in the presence of high salt concentration to inhibit lipoprotein lipase. Cholesterol esterifying activity was identified in feline plasma and was typical of LCAT, in that it was dependent on apolipoprotein A-I as a cofactor. The intra-assay and interassay coefficients of variation for measurement of lipoprotein lipase, hepatic lipase, and LCAT activities were 18.4, 4.6, and 7.2%, and 20.4, 10.7, and 5.3%, respectively. Appreciable cholesteryl ester transfer protein activity was not detected in either undiluted or diluted plasma. These methods were subsequently used to investigate the effects of pregnancy and lactation on lipoprotein metabolism in a group of 10 queens. Plasma concentrations of cholesterol and triglycerides were unaltered during pregnancy, but the concentrations of VLDL-cholesterol increased and those of HDL-cholesterol decreased. During lactation, the concentrations of cholesterol and triglycerides decreased owing to reductions in VLDL-cholesterol and LDL-cholesterol concentrations and continued suppression of HDL-cholesterol. These changes were associated with alterations in the activities of lipoprotein lipase, which increased after parturition, and hepatic lipase, which increased during pregnancy and lactation, that may help explain their metabolic origins. The activity of LCAT remained unchanged.

The oil of Juniperus communis (JC) which is among medicinal plants, has many pharmacological activities. In this study, the effects of JC oil on serum paraoxonase (PON1), pancreatic enzymes levels and lipid levels in experimental diabetic rats were investigated.Thirty-two male Wistar-Albino rats (250-300g) were used. The rats were dividedequally into four groups, control (C), diabetes (D), JC oil (J), and diabetes + JC oil (DJ). D and DJ groups wereintraperitoneally (IP) injected with 45 mg/kg streptozotocin (STZ). JC oil was administered as 200 mg/kg/21days by oral gavage in J and DJ groups.Total cholesterol (TC) and triglyceride (TG) levels were significantly decreased in the J and DJgroups when compared to C and D groups (p≤0.001). There was no difference in TG levels between D andcontrol group (p≥0.05). Lipoprotein levels were not statistically significant between any group (p≥0.05).Comparing to the control group in the diabetes and DJ groups; significant decreased amylase levels andincreased lipase levels (p≤0.001) was observed. Paraoxonase activity in D group was statistically lower thanin the other groups (p≤0.05). There is no significant difference between the C group and the Jgroup (p>0.05).PON1 level has a significant elevation in the DJ in comparison with the D group (p≤0.05). As a result, JC oil caused an increase in antioxidant PON1 enzyme level and a decrease in lipidlevels in diabetes. The data obtained are supportive that JC oil may be a potential protective effect againstdiabetes-associated complications.

Bovine pneumonic pasteurellosis vaccines incorporate various antigens of Mannheimia haemolytica, including the acknowledged virulence factor leukotoxin (Lkt), and Gs60, a surface lipoprotein. To examine the role of antibodies to Gs60 in protection, an enzyme-linked immunosorbent assay (ELISA) was developed for retrospective analysis of serum samples from previous trials in which vaccines containing native or recombinant Gs60 were administered parenterally. The analysis revealed a positive correlation between the titer of antibodies to Gs60 and protection against experimental challenge in both vaccinates and naturally exposed controls. There was a strong correlation between production of IgG antibodies to Gs60 and Lkt neutralizing antibodies. Analysis of the relationship between the serum antibody titers and resistance to experimental challenge using linear statistical models revealed a significant association between prechallenge titers of serum antibodies to Lkt and protection. Further analysis suggested that antibodies against Gs60 were beneficial when Lkt neutralizing antibody titers were low.

Serum lipoprotein concentrations, routine serum biochemical values, and morphologic changes of the liver were evaluated in cats undergoing weight loss. Food was withheld from 6 obese and 6 control cats for 3 days (days 0 to 2), followed by feeding 50% of previous food intake for 26 days (days 3 to 28). Percutaneous liver biopsy specimens were obtained from all cats on days 0, 7, 14, and 28. Blood samples for serum biochemical analysis and lipoprotein profiles were obtained on days 0, 3, 7, 14, and 28. All cats lost weight throughout the study, and none developed signs of chemical illness, including those of idiopathic hepatic lipidosis syndrome. Serum total cholesterol concentrations decreased initially in all cats, but rapidly returned to normal after day 3 in obese cats, suggesting altered cholesterol metabolism during dietary restriction. Low-density lipoprotein concentrations decreased throughout the study in control cats, but were unchanged in obese cats. Examination of liver biopsy specimens from each cat revealed minimal lipid accumulation in all specimens, although some specimens contained hydropic degeneration.

Alterations in serum lipid and lipoprotein concentrations in ponies with experimentally induced liver disease were investigated. Hepatocellular damage was induced, using a nonlethal dose of carbon tetrachloride. In a separate group of ponies, obstructive jaundice was induced by surgical ligation of the common bile duct. Over a 6-day period, blood samples were obtained from ponies after treatment with carbon tetrachloride and for 12 days in ponies subjected to surgery. Serum cholesterol and triglyceride concentrations were unaffected in both groups of ponies, except for significantly (P < 0.01) high triglyceride concentration in ponies of the ligated group during the second postsurgical week. This increase was most likely attributable to anorexia observed during that period. Hyperbilirubinemia was observed early in ponies of the ligated group; most of the bilirubin was of the conjugated type. Using electrophoretic and ultracentrifugal methods, serum lipoprotein alterations were detected only in ponies of the ligated group. Increases of very low-density and low-density hpoprotein cholesterol concentrations and decrease in high-density lipoprotein cholesterol concentration were found. Although no changes were seen in total serum cholesterol concentration, a redistribution of lipoprotein cholesterol was observed in ponies of the ligated group. Similar alterations in lipoprotein distribution have been found in dogs, rats, and human beings with obstructive jaundice and cholestasis. The association between serum lecithin:cholesterol acyl transferase activities and these lipoprotein alterations remains to be elucidated.