Exogenous paraoxonase‐1 during oocyte maturation improves bovine embryo development in vitro

Paraoxonase‐1 (PON1) is an enzyme found in serum and follicular fluid that protects cell membrane and circulating lipids against oxidative damage. The aims of this study were to measure the direct effects of recombinant PON1 (rPON1) on bovine oocyte maturation at the molecular level (gene expression) and to measure the carry‐over effects of PON1 on pre‐implantation embryo development in vitro. COCs were submitted to IVM with the addition of 0.0, 0.02, 0.04 and 0.08 mg ml^?1 of rPON1, corresponding to an average PON1 arylesterase enzyme activity of 2.2 ± 0.4, 15.5 ± 1.5, 30.2 ± 3.0 and 57.9 ± 5.0 U ml^?1, respectively. The results indicated that addition of rPON1 during IVM improved embryo development in a dose‐dependent manner as D7 embryo development was 22.2%, 29.4%, 32.2% and 37.0% for the treatment groups, respectively (p = 0.02). In conclusion, addition of PON1 enzyme during IVM exerted dose‐related positive effects on embryo development rates to blastocysts.     

Long Chain Fatty Acids of Diet as Factors Influencing Reproduction in Cattle

Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n-6 and n-3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n-6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n-3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle.     

Rotavirus infections in calves in dairy herds

Neonatal calf diarrhoea was studied in 115 calves of one dairy herd from January 1976 to June 1977. Two syndromes could be distinguished: a mild and short lasting 'early diarrhoea' within the first three days of life and a usually more severe 'late diarrhoea' from the fourth to the 14th day of life. The latter type of diarrhoea occurred almost exclusively during the first half of the year. Thirty-four out of 45 calves with late diarrhoea excreted rotaviruses, whereas only one of 34 calves with early diarrhoea excreted virus. In addition, rotavirus excretion was found in 11 calves that either remained healthy or had recovered from diarrhoea before virus was first detected. Similar findings were obtained in the spring of 1978 but in addition bovine coronavirus was recovered from four calves with late diarrhoea and from three healthy calves. One faecal sample obtained from a calf with diarrhoea on day 2 yielded K99+ Escherichia coli. Nearly all cows excreted rotavirus-specific antibodies in their colostrum but no relationship was found between the initial colostral antibody titre against rotavirus and the development of rotavirus-associated diarrhoea in the calf.     

Enrichment of higher molecular weight fractions in inulin

Inulin (general formulas GFn and Fm, with G = anhydroglucose and F = anhydrofructose) naturally occurs as a homologous series of oligo- and polysaccharides with different chain lengths. For reasons of growing interest in the food and pet food industries, the short chain inulins have to be separated from their long chain analogues because their properties (digestibility, prebiotic activity and health promoting potential, caloric value, sweetening power, water binding capacity, etc.) differ substantially. To study these properties in relation to the number average degree of polymerization (DPn), ultrafiltration, specific crystallization from aqueous solution, and precipitation from solvent/water mixtures were used to enrich native chicory and dahlia inulin in the higher molecular weight fractions. Depending on the membrane module used, the DPn of chicory inulin (DPn = 8.1) and dahlia inulin (DPn = 29) could be increased by ultrafiltration to a maximum value of, respectively, 22 and 43. With crystallization from aqueous solutions (25 degrees C), similar results were obtained but at a much higher yield. Finally, long chain inulin could be precipitated from aqueous solutions in the presence of high concentrations of methanol, ethanol, and acetone. Acetone demonstrated to be the best solvent system to increase the DPn, followed by ethanol and methanol. However, for safety reasons and food purposes, ethanol was evaluated to be the best choice. With ethanol, the DPn could be raised to 25 for chicory inulin and up to 40 for dahlia inulin.     

Meningoencephalomyelitis in a foal due to Salmonella agona infection

CASE HISTORY: A neonatal Thoroughbred foal was presented with rib fractures and left forelimb lameness secondary to dystocia.

CLINICAL FINDINGS: The foal developed a head tilt, seizures and watery diarrhoea during hospitalisation and died at 7 days of age. Histological examination of the brain and spinal cord revealed a suppurative meningoencephalomyelitis with vasculitis, and numerous intralesional, gram-negative bacilli. Similar microscopic lesions were noted in the lungs, renal medullary interstitium, and umbilicus. Bacilli in the brain, spinal cord and umbilicus were identified immunohistochemically as Salmonella group B. Salmonella agona was isolated in pure culture from the brain, lung, liver, kidney, and intestine.

CONCLUSION: This is the first report of meningoencephalomyelitis and septicaemia due to Salmonella infection in an equine neonate.     

Paraoxonase 1 (PON1) activity in serum,follicular fluid and seminal plasma of sheep

This work aimed to describe the activity of paraoxonase 1 (PON1) in serum, follicular fluid and seminal plasma of sheep. Average serum PON1 activity was 286.8 ± 96.2 U/ml in females and 237.6 ± 18.9 U/ml in males. There was a positive correlation between PON1 activity in serum and follicular fluid in females, being twice higher in serum than in follicular fluid (148.8 ± 15.7 U/ml). PON1 activity in males’ serum was 10‐fold higher than in seminal plasma (21.18 ± 14.2 U/ml), and there was no correlation between PON1 activity in both compartments. Finally, this work suggests that PON1 activity of in sheep is higher compared to other mammalian species, and there is an association between PON1 in serum and follicular fluid only.     

DNA synthesis generates terminal duplications that seal end-to-end chromosome fusions

End-to-end chromosome fusions that occur in the context of telomerase deficiency can trigger genomic duplications. For more than 70 years, these duplications have been attributed solely to breakage-fusion-bridge cycles. To test this hypothesis, we examined end-to-end fusions isolated from Caenorhabditis elegans telomere replication mutants. Genome-level rearrangements revealed fused chromosome ends having interrupted terminal duplications accompanied by template-switching events. These features are very similar to disease-associated duplications of interstitial segments of the human genome. A model termed Fork Stalling and Template Switching has been proposed previously to explain such duplications, where promiscuous replication of large, noncontiguous segments of the genome occurs. Thus, a DNA synthesis-based process may create duplications that seal end-to-end fusions, in the absence of breakage-fusion-bridge cycles.     

Chronologic and physiologic age affect replicative life-span of fibroblasts from diabetic, prediabetic, and normal donors

Cultured skin fibroblasts from subjects with clinically apparent diabetes mellitus and from subjects genetically predisposed to diabetes have a replicative lifespan that is inversely related to donor age. Fibroblasts from carefully defined normal subjects not predisposed to diabetes fail to show this correlation. The data support the idea that physiologic status of the tissue donor is a more precise determinant of fibroblast replicative lifespan than chronologic age.     

Supplementation with Calcium Salts of Linoleic and trans-Octadecenoic Acids Improves Fertility of Lactating Dairy Cows

Objectives were to evaluate effects of feeding a calcium salt rich in linoleic and trans -octadecenoic acids (LTFA) on synthesis of prostaglandin F_2α based on its metabolite (PGFM), uterine involution and pregnancy rates in lactating dairy cows. Five hundred and eleven Holstein cows were blocked according to parity, body condition score and milk yield in the previous lactation. Primiparous and multiparous cows were randomly assigned to one of the two treatments consisting of calcium salt (2% diet dry matter) of either palm oil (PO) or LTFA from 25 days prepartum to 80 days of lactation. Cows were time-inseminated at 70 ± 3 days postpartum. Feeding LTFA tended (p = 0.08) to decrease the incidence of puerperal metritis (15.1% vs 8.8%). Primiparous cows supplemented with LTFA showed larger increase in plasma PGFM concentration at day 1 postpartum (17018 vs 6897 p m ). Pregnancy rate after first insemination tended (p = 0.07) to be greater at 27 days after insemination (37.9% vs 28.6%), and was greater (p = 0.05) at 41 days after insemination (35.5% vs 25.8%) for cows fed LTFA compared with PO. These results indicate that unsaturated fatty acids fed in a rumen inert form have the potential to modulate reproductive events and improve pregnancy rates in lactating dairy cows.