Characterization and expression analysis of chitinase genes (CHIT1, CHIT2 and CHIT3) in turbot (Scophthalmus maximus L.) following bacterial challenge.

Chitinases are hydrolytic enzymes which have been employed to breakdown chitin coats of pathogenic microorganisms, thereby weaken the defense system of several pathogens and insects. In this regard, we identified the chitinase genes of turbot and characterized their expression patterns in mucosal tissues following Vibrio anguillarum and Streptococcus iniae challenge. In present study, transcripts of three chitinase genes (CHIT1, CHIT2 and CHIT3) were captured, as well as their protein structures and expression patterns following different bacterial infection were also characterized. The chitinases were widely expressed in all tested tissues with the highest expression levels of CHIT1 and CHIT2 in intestine, and CHIT3 in skin. Finally, these three genes showed different expression patterns following bacterial challenge. The significant quick induction of chitinases in mucosal surfaces against infection indicated their key roles to prevent pathogen attachment and entry in mucosal immunity. Functional studies should further characterize the chitinases and avail utilization of their function to increase the disease resistance in maintaining the integrity of the mucosal barriers against infection and facilitating the disease resistant family/strain selection in turbot.

An impact of l-histidine on the phosphorylation and stability of pyruvate kinase at low NaCl level.

As one of the key rate limiting enzymes in glycolysis process, the characteristics of pyruvate kinase (PK) play an important role in regulating the muscle quality. Given the close relationship between kinase phosphorylation level and its stability, the present study investigated the impact of exogenous l-histidine (l-his) on PK phosphorylation and activity at 1% NaCl level in the early postmortem. An incubation system was also constructed and the results showed that the introduction of 0.06% l-his caused the dephosphorylation and increased the activity of PK at 1% NaCl. Compared with 1% NaCl treatment, three differential phosphorylation sites were produced when l-his was introduced. The PK secondary structure was shift from order to disorder, leading to a distinct degradation. This present study provided us with inspiration that meat quality could be improved by exogenous l-his at early postmortem under low NaCl conditions.

Influence of dietary Salicornia europaea L. extract supplementation on feed efficiency of Altay sheep by modifying their gastrointestinal bacteria communities.

This experiment aimed to examine the impact of Salicornia europaea L. extract on sheep growth performance, rumen fermentation variables, nutrient apparent digestibility, and gastrointestinal microbial diversity. Forty-eight male Altay sheep, weighing 32.5 ± 2.8 kg and approximately 3.5 months old, were chosen. Four dietary treatments, each consisting of four replicates and three sheep per replicate, were distributed randomly to the sheep. The pelleted total mixed ration containing Salicornia europaea L. extract at 0.0, 0.2, 0.4, and 0.6% DM was freely available to the sheep in the four treatment groups. The 56-day experiment consisted of 45 days of measurements followed by 11 days of adaptation. The growth performance was not affected by nutrition Salicornia europaea L. extract (p ≤ 0.05), but the feed-to-gain ratio was reduced when the extract was given at 0.4% DM (p ≤ 0.05). Compared to the 0 and 0.2% treatments, the apparent digestibility of DM, OM, NDF, and ADF was substantially greater in the 0.4, and 0.6% treatments. Furthermore, compared to sheep in the 0 and 0.2% groups, sheep in the 0.6% group had a noticeably higher apparent digestibility of CP. As the amount of Salicornia europaea L. extract added to the rumen fluid rose, the molar ratio of acetic acid increased. In contrast, the molar ratio of propionic acid gradually decreased, and the total volatile fatty acid content gradually reduced. Thus, adding a suitable quantity of Salicornia europaea L. extract to the sheep ration is natural and secure, which may improve the environmental sustainability of small ruminant production systems.