Macro‐geographical differences influenced by family‐based expression on cultured pearl grade,shape and colour in the black‐lip ‘pearl oyster’ Pinctada margaritifera: a preliminary bi‐local case study in French Polynesia

In French Polynesia, the aquaculture of Pinctada margaritifera is carried out in numerous grow‐out sites, located over three archipelagos (Gambier, Society and Tuamotu). To evaluate the impact of macro‐geographical effects of these growing sites on pearl quality traits, five hatcheries produced families were used as homogeneous donor oysters in an experimental graft. The molluscs were then reared in two commercial locations: Tahaa Island (Society) and Rangiroa atoll (Tuamotu). At harvest, eight pearl quality traits were recorded and compared: surface defects, lustre, grade, circles, shape categories, darkness level, body and secondary colour and visual colour categories. Overall inter‐site comparison revealed that: (1) all traits were affected by grow‐out location except for lustre and round shape, and (2) a higher mean rate of valuable pearls was produced in Rangiroa. Indeed, for pearl grade, Rangiroa showed twice as many A‐B and less reject samples than Tahaa. This was related to the number of surface defects (grade component): in Rangiroa, twice as many pearls had no defects and less pearls had up to 10 defects. Concerning pearl shape, more circled and baroque pearls were found in Tahaa (+10%). For colour variation, 10% more pearls have an attractive green overtone in Rangiroa than in Tahaa, where more grey body colour were harvested. Lustre does not seem to be affected by these two culture site (except at a family scale). This is the first time P. margaritifera donor family have been shown to vary in the quality of pearls they produce depending on their grow‐out location.     

Effect of mitochondrial uncoupling and glycolysis inhibition on ram sperm functionality

Studies have demonstrated the importance of mitochondria to sperm functionality, as the main source of ATP for cellular homoeostasis and motility. However, the role of mitochondria on sperm metabolism is still controversial. Studies indicate that, for some species, glycolysis may be the main mechanism for sperm energy production. For ram sperm, such pathway is not clear. Thus, we evaluated ram sperm in response to mitochondrial uncoupling and glycolysis inhibition aiming to assess the importance of each pathway for sperm functionality. Statistical analysis was performed by the SAS System for Windows, using the General Linear Model Procedure. Data were tested for residue normality and variance homogeneity. A p < .05 was considered significant. Groups treated with the mitochondrial uncoupler Carbonyl cyanide 3 chlorophenylhydrazone (CCCP) showed a decrease in the percentage of cells with low mitochondrial activity and high mitochondrial membrane potential. We also observed that the highest CCCP concentration promotes a decrease in sperm susceptibility to lipid peroxidation. Regardless the lack of effect of CCCP on total motility, this substance induced significant alterations on sperm kinetics. Besides the interference of CCCP on spermatic movement patterns, it was also possible to observe such an effect in samples treated with the inhibitor of glycolysis (2‐deoxy‐d ‐glucose, DOG). Furthermore, treatment with DOG also led to a dose‐dependent increase in sperm susceptibility to lipid peroxidation. Based on our results, we suggest that the glycolysis appears to be as important as oxidative phosphorylation for ovine sperm kinetics as this mechanism is capable of maintaining full motility when most of the cells have a low mitochondrial membrane potential. Furthermore, we found that changes in the glycolytic pathway trough glycolysis inhibition are likely involved in mitochondrial dysfunction and sperm oxidative unbalance.     

Lectin Histochemistry as a Tool to Identify Apoptotic Cells in the Seminiferous Epithelium of Syrian Hamster (Mesocricetus auratus) Subjected to Short Photoperiod

Lectins have been widely used to study the pattern of cellular glycoconjugates in numerous species. In the process of cellular apoptosis, it has been observed that changes occur in the membrane sugar sequences of these apoptotic cells. The aim of our work was to identify which lectins, out of an extensive battery of the same (PNA, SBA, HPA, LTA, Con‐A, UEA‐I, WGA, DBA, MAA, GNA, AAA, SNA), show affinity for germinal cells in apoptosis, at what stage of cell death they do so and in which germinal cell types they can be detected. For this, we studied testis sections during testicular regression in Syrian hamster (Mesocricetus auratus) subjected to short photoperiod. Several lectins showed an affinity for the glycoconjugate residues of germ cells in apoptosis: Gal β1,3‐GalNAcα1, α‐d ‐mannose, N‐acetylgalactosamine and l ‐fucose. Furthermore, lectin specificity was observed for some specific germinal cells and in certain stages of apoptosis. It was also observed that one of these lectins (PNA) showed affinity for Sertoli cells undergoing apoptosis. Therefore, we conclude that the use of lectin histochemistry could be a very useful tool for studying apoptosis in the seminiferous epithelium because of the specificity shown towards germinal cells in pathological or experimentally induced epithelial depletion models.     

Influence of dietary protein supply on resistance to experimental infections with Haemonchus contortus in Ile de France and Santa Ines lambs

The effect of Haemonchus contortus infection in sheep fed with a moderate and high protein content diet was evaluated in two breeds of sheep. Forty-eight Ile de France and Santa Ines lambs were maintained indoors since birth, in worm-free conditions. The lambs were allocated after weaning in four groups of six animals per breed, which were either infected or remain uninfected and given access to either a moderately or highly metabolizable protein diet. The moderately and highly metabolizable protein diets were calculated to supply 75 and 129 g metabolizable protein per kg of dry matter (MP/kg DM), respectively. The infection consisted of a trickle infection with 300 infective larvae, three times a week, for 12 weeks. Significant differences were observed for mast cell, globule leukocyte and eosinophil counts in the abomasal mucosa of the infected groups compared to the control of both breeds (P<0.05), regardless of the diet supplied. Significantly higher IgA anti-L5 antibody was detected in the infected Santa Ines groups than in the infected Ile de France groups (P<0.05). Increased metabolizable protein supply resulted in larger body weight gain and higher packed cell volumes for both breeds (P<0.05). Both breeds showed an increased ability to withstand the pathophysiological effects of H. contortus infection when given access to the highly metabolizable protein diet. However, increased metabolizable protein supply resulted in reduced worm burdens in Santa Ines lambs but not in the Ile de France lambs (P<0.05). The present results show that the increase in protein content in growing lamb diets may benefit resistance and resilience to gastrointestinal parasites but that these benefits may vary among breeds.     

Evaluation of the sexual dimorphism in Mangalarga Marchador horses using discriminant analysis

This study used discriminant analysis to evaluate body measures and sexual dimorphism in Mangalarga Marchador horses. Discriminant analysis is a multivariate method that generates functions to classify animals using a prior criterion. In this study a prior criterion is male or female. The study analyzed 25 linear and 11 angular measures obtained from 25 stallions and 56 mares registered with the Mangalarga Marchador Brazilian Breeders Association. Knee girth, cannon girth, chest width, chest girth, back-loin length, hip width, distance from elbow to knee, hind limb hoof length, head width, shoulder length, and body length were found to be linear measures that provided evidence of sexual dimorphism. Angular measures with evidence of sexual dimorphism were shoulder–humerus, metacarpal–phalanx, coxae–femur, and femur–tibial angles. Stallions were larger than mares for almost all linear measures, except for back-loin length, hip width, and distance from elbow to knee. Shoulder–humerus and coxal–femur angles were larger in mares, while metacarpal–phalanx and femur–tibial angles were larger in stallions. Using linear measures, two mares were classified as stallions and three stallions were classified as mares. For angular measures, two other mares were classified as stallions and three other stallions were classified as mares. The discriminant functions can be useful for the selection of horses and to avoid registration of animals not meeting the phenotypic standards of the breed association.     

Influence of Heat Stress on the Cortisol and Oxidant‐Antioxidants Balance During Oestrous Phase in Buffalo‐Cows (Bubalus bubalis): Thermo‐protective Role of Antioxidant Treatment

In the present study, the effect of heat stress, which is commonly observed in the animals of Upper Egypt area in summer, as well as the effect of antioxidant treatment as a thermo‐protective was examined. In this study, the animals (n = 120) were divided into winter group (n = 40, bred during winter) and summer group (n = 80, bred during summer) as well as, animals in the summer group were divided into first subgroup animals (n = 40) and injected with Viteselen intramuscularly (15 ml) twice weekly for 10 weeks and second subgroup animals (n = 40) were not treated (as control). Serum levels of progesterone (P4), oestradiol (E2), cortisol, superoxide dismutase (SOD), lipid peroxidase (LPO) and nitric oxide (NO) were measured. The pregnancy rate of all animals was detected rectally. The levels of oestradiol and the activity of the antioxidant SOD were decreased in serum of animals in behavioural oestrus during summer as compared with those in winter. During the same time period the levels of oxidants such as LPO and NO were increased in the serum of animals again in the phase of oestrus. In another group of animals treated by intramuscular injection with 15 ml viteselen (antioxidant) twice weekly for 6 weeks during hot months, the activities of serum SOD showed an increase and the levels of oxidants and cortisol decreased. Moreover, the levels of oestradiol were increased during the oestrous behaviour. The pregnancy rate was decreased in animals under heat stress and the pregnancy rate was enhanced dramatically when these animals received antioxidants during the heat stress. This means that the heat‐stress in Upper Egypt may affect the fertility of animals and pregnancy rate and this effect may be through an increased production of free radicals and decreased production of antioxidants as well as increased levels of cortisol. Treatment of animals or supplementation with antioxidants before the beginning of months of heat‐stress and also during the stress period may correct the infertility due to heat‐stress through the decrease in cortisol secretion and a decrease in the oxidative stress. These results resulted in an increase in pregnancy rate in treated animals.