Effect of n‐3 PUFA‐rich fish oil supplementation during late gestation on kidding,uterine involution and resumption of follicular activity in goat

We have shown that dietary supplementation of n‐3 polyunsaturated fatty acid (n‐3 PUFA)‐rich fish oil (FO) around the breeding time improved the utero‐ovarian functions in the goat. Here, we investigated the effect of FO supplementation during the periparturient period on serum n‐3 PUFA, prostaglandin F_2α metabolite (PGFM), placental expulsion, uterine involution, resumption of oestrus and neonatal vigour. Rohilkhandi goat in advanced gestation (n = 16) was divided into two equal groups. One group was supplemented with FO containing 26% n‐3 long‐chain PUFA at the rate of 156 mg per kg body weight, while the control group was fed isocaloric palm oil (PO) from ?3 to +3 week of kidding. Dietary FO increased serum concentration of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by 7.3‐ and 6.6‐fold, respectively, after 6 weeks of supplementation. Goats in FO group expelled the foetal membranes 99.1 min earlier (p < .01) than those of PO group. Further, dietary FO significantly decreased the serum PGFM on day 7 post‐partum. However, no difference was found on uterine involution, which was complete by day 20 post‐partum in either group. Resumption of follicular activity by day 5 post‐partum was 87.5% in the FO as compared to 25% in the PO group (p < .05). Similarly, occurrence of behavioural oestrus by day 90 post‐partum was 57.1% in goats of the FO group while none of does was in the PO group (p < .01) expressed oestrus. It was concluded that feeding FO‐rich diet during ?3 to +3 weeks of kidding decreased the PGFM till day 7 post‐partum, hastened the expulsion of foetal membranes and reduced the time from kidding to first post‐partum oestrus in Rohilkhandi does.     

Resistance to ETEC F4/F18–mediated piglet diarrhoea: opening the gene black box

Diarrhoea, a significant problem in pig rearing industry affecting pre- and post-weaning piglets is caused by enterotoxigenic Escherichia coli (ETEC). The ETEC are classified as per the fimbriae types which are responsible for bacterial attachment with enterocytes and release of toxins causing diarrhoea. However, genetic difference exists for susceptibility to ETEC infection in piglets. The different phenotypes found in pigs determine their (pigs’) susceptibility or resistance towards fimbrial subtypes/variants (F4ab, F4ac, F4ad and F18). Specific receptors are present on intestinal epithelium for attachment of these fimbriae, which do not express to same level in all animals. This differential expression is genetically determined and thus their genetic causes (may be putative candidate gene or mutations) render some animals resistant or susceptible to one or more fimbrial subtypes. Genetic linkage studies have revealed the mapping location of the receptor loci for the two most frequent variants F4ab and F4ac to SSC13q41 (i.e. q arm of 13th chromosome of Sus scrofa). Some SNPs have been identified in mucin gene family, transferring receptor gene, fucosyltransferase 1 gene and swine leucocyte antigen locus that are proposed to be linked mutations for resistance/susceptibility towards ETEC diarrhoea. However, owing to the variety of fimbrial types and subtypes, it would be difficult to identify a single causative mutation and the candidate loci may involve more number of genes/regions. In this review, we focus on the genetic mutations in genes involved in imparting resistance/susceptibility to F4 or F18 ETEC diarrhoea and possibilities to use them as marker for selection against susceptible animals.

     

A rapid,inexpensive, and semi-quantitative method for determining pollen tube extension using fluorescence

Background

To identify plant genes involved in various key traits, QTL mapping is a powerful approach. This approach is based on the use of mapped molecular markers to identify genomic regions controlling quantitative traits followed by a fine mapping and eventually positional cloning of candidate genes. Mapping technologies using SNP markers are still rather expensive and not feasible in every laboratory. In contrast, microsatellite (also called SSR for Simple Sequence Repeat) markers are technologically less demanding and less costly for any laboratory interested in genetic mapping.

Results

In this study, we present the development and the characterization of a panel of 96 highly polymorphic SSR markers along the Arabidopsis thaliana genome allowing QTL mapping among accessions of the Versailles 24 core collection that covers a high percentage of the A. thaliana genetic diversity. These markers can be used for any QTL mapping analysis involving any of these accessions. We optimized the use of these markers in order to reveal polymorphism using standard PCR conditions and agarose gel electrophoresis. In addition, we showed that the use of only three of these markers allows differentiating all 24 accessions which makes this set of markers a powerful tool to control accession identity or any cross between any of these accessions.

Conclusion

The set of SSR markers developed in this study provides a simple and efficient tool for any laboratory focusing on QTL mapping in A. thaliana and a simple means to control seed stock or crosses between accessions.