Depletion of serum alternative complement pathway activity in gilthead seabream caused by α-tocopherol and n-3 HUFA dietary deficiencies

Studies on the alternative complement pathway (ACP) activity in fish have suggested the particular relevance of this pathway as a non-specific immune mechanism being its activation directly related with the availability of certain nutrients. In the present study ACP activity in gilthead seabream fed different dietary levels of a-tocopherol and n-3 HUFA deficiencies was studied under different stress conditions (overcrowding and repetitive chasing).A reduction in ACP activity was found when diets with deficiencies in -tocopherol and n-3 HUFA were assayed at any of the experimental conditions assayed. Levels of plasma cortisol were similar to those of fish after crowding stress subjected to dietary deficiencies at low stocking density, suggesting that dietary deficiencies produced a chronic elevation of cortisol. When fish were subjected to repetitive chasing, plasma cortisol from fish fed control diet showed a progressive increase whereas plasma cortisol levels from both dietary deficient groups showed a transitory peak 4 days after the beginning of the repetitive chasing. However, ACP activity levels of fish fed deficient diets remained lower than the control group and constant during chasing period. These results suggest that both a-tocopherol and n-3 HUFA nutritional deficiencies rather than stress are an important determinant of fish complement activity.     

Influence of Temperament Score and Handling Facility on Stress,Reproductive Hormone Concentrations,and Fixed Time AI Pregnancy Rates in Beef Heifers

The objectives were (i) to evaluate the effect of temperament, determined by modified 2‐point chute exit and gait score, on artificial insemination (AI) pregnancy rates in beef heifers following fixed time AI and (ii) to determine the effect of temperament on cortisol, substance‐P, prolactin and progesterone at initiation of synchronization and at the time of AI. Angus beef heifers (n = 967) at eight locations were included in this study. At the initiation of synchronization (Day 0 = initiation of synchronization), all heifers received a body condition score (BCS), and temperament score (0 = calm; slow exit and walk or 1 = excitable; fast exit or jump or trot or run). Blood samples were collected from a sub‐population of heifers (n = 86) at both synchronization initiation and the time of AI to determine the differences in serum progesterone, cortisol, prolactin and substance‐P concentrations between temperament groups. Heifers were synchronized with 5‐day CO‐Synch+ controlled internal drug release (CIDR) protocol and were inseminated at 56 h after CIDR removal. Heifers were examined for pregnancy by ultrasound 70 days after AI to determine AI pregnancy. Controlling for synchronization treatment (p = 0.03), facility design (p = 0.05), and cattle handling facility design by temperament score interaction (p = 0.02), the AI pregnancy differed between heifers with excitable and calm temperament (51.9% vs 60.3%; p = 0.01). The alley‐way with acute bends and turns, and long straight alley‐way had lower AI pregnancy rate than did the semicircular alley‐way (53.5%, 56.3% and 67.0% respectively; p = 0.05). The serum hormone concentrations differed significantly between different types of cattle handling facility (p < 0.05). The cattle handling facility design by temperament group interactions significantly influenced progesterone (p = 0.01), cortisol (p = 0.01), prolactin (p = 0.02) and substance‐P (p = 0.04) both at the initiation of synchronization and at the time of AI. Inter‐ and intra‐rater agreement for temperament scoring were moderate and good (Kappa = 0.596 ± 0.07 and 0.797 ± 0.11) respectively. The predictive value for calm and pregnant to AI was 0.87, and excited and non‐pregnant to AI was 0.76. In conclusion, the modified 2‐point temperament scoring method can be used to identify heifers with excitable temperament. Heifers with excitable temperament had lower AI pregnancy. Further, cattle handling facility design influenced the temperament and AI pregnancy.     

Determination of Feeder Cell‐Based Cellular Niches Supporting the Colonization and Maintenance of Spermatogonial Stem Cells from Prepubertal Domestic Cat Testes

Recently, isolation and in vitro culture of putative spermatogonial stem cells (SSCs) in the domestic cat have been conducted. However, the cellular niche conditions that facilitate the establishment and long‐term maintenance of feline SSCs (FSSCs) have not been described. Therefore, we investigated the type of feeder cells used to stimulate colony formation and growth of FSSCs among the various factors in the FSSC niche. Spermatogonial stem cells isolated from feline testes were cultured on mitotically inactivated testicular stromal cells (TSCs) derived from cats, dogs and mice, and mouse embryonic fibroblasts (MEFs). The formation and growth of colonies derived from SSCs cultured on each type of feeder cell were identified at passage 0, and the morphology, alkaline phosphatase (AP) activity and expression of SSC‐specific genes in surviving colonies were investigated at passage 4. Among these diverse feeder cells, TSCs from cat showed the greatest colony formation, growth and maintenance of FSSCs, and SSC colonies cultured by passage 4 showed a typical dome‐shaped morphology, AP activity and expression of SSC‐specific genes (NANOG, OCT4, SOX2 and CD9). Accordingly, these results demonstrate that feline TSCs could be used as feeder cells to support the establishment and maintenance of SSCs from domestic cats.     

Alteration of liver and muscle fatty acid composition in gilthead seabream (Sparus aurata) juveniles held at high stocking density and fed an essential fatty acid deficient diet

The aim of the present study was to determine the combined effect of both stress and EFA deficiency on several biological and biochemical parameters. Fish were fed during 15 weeks two isocaloric and isoproteic diets: a control diet based on fish oil and formulated to meet the n-3 HUFA requirements for this species (1.5% of n-3 HUFA) and a deficient diet containing beef tallow and formulated to be deficient in n-3 HUFA. Each experimental diet was evaluated both at high and low stocking densities (10 and 3.2 kg m^–3 of initial density, respectively).High stocking density produced a chronic stress situation with elevation of plasma cortisol levels. It also caused a reduction in hepatosomatic index and liver lipid contents, increasing the oleic acid/n-3 HUFA ratios in the polar lipids. Fish fed the EFA deficient diet at low stocking density showed common deficiency symptoms. High stocking density in fish fed the EFA deficient diet induced a higher degree of EFA deficiency symptoms leading to mortality, liver steatosis, liver lipid deposition, reduced muscle lipid and reduced n-3 HUFA contents, which particularly affected EPA, but not DHA, suggesting a preferential retention of the latter fatty acid, specially in the phosphoglycerides fraction.     

The genetic structure of Mytilus chilensis (Hupé 1854) populations along the Chilean coast based on RAPDs analysis

The Chilean blue mussel Mytilus chilensis is an important commercial species. However, little has been published on the population genetics of this species, despite the need to implement management and conservation policies. Randomly amplified polymorphic DNA‐polymerase chain reaction analysis was used to estimate genetic variation within and between eight natural populations along the whole range of its Chilean natural distribution (ca. 1900 km from Arauco (VIII Region) to Punta Arenas (XII Region)). The values of Nei's unbiased genetic distance, D (0.030–0.107), among populations were small, despite the large geographic separation. A mantel test using 50 000 randomizations showed evidence for a significant correlation (r=0.74, P<0.05) between genetic and geographic (coastal) distance. Punta Arenas population was the most genetically differentiated from the others, although the scale of differentiation was not large (D=0.076–0.107). The levels of gene flow (Nm=1.55) found in this study prevent differentiation among populations by genetic drift. This is the result of the long‐lived planktotrophic larvae of M. chilensis, which provides this species with considerable dispersal ability throughout its range, which is favoured by the ocean currents along the Chilean coast. A restricted larval dispersal towards the north due to the Cape Horn Current derived from the West Wind Drift could be the cause of the higher genetic differentiation of Punta Arenas population from the northern populations. For management purposes of the M. chilensis fishery, the results provide no evidence for discrete stocks, with the possible exception of the Punta Arenas population. The present study provides the baseline data in order to continue further characterization of these mussel populations, considering the great increase in aquaculture of this species.     

Viability of Extended Goat Semen Stored at Refrigerated Condition

Due to the small volume of goat semen ejaculate, just a few doses of goat semen were produced when the sperm concentration is 100 × 10^/mL. The study was aimed to determine the viability of extended goat semen at refrigerated condition at 5 ℃ using varying sperm concentrations and evaluated if sperm concentration lower than 100 × 10^6/mL would affect the motility, viability and sperm morphology at refrigerated condition. Using an artificial vagina, ejaculated goat semen was collected from goat semen donor aged 1.5 year. Physical evaluation of the collected semen showed an average volume of 0.54 mL, mean pH of 6.8 and a milky white color with thick consistency indicative of high concentration. Fresh goat semen had an initial average of 76% with an average initial sperm concentration of 128 × 10^/mL. The semen was divided into four treatments： sperm concentration of 100× 10^/mL, 75 × 10^/mL, 50 × 10^/mL and 25 × 10^/mL, and were stored at 5 ℃ for a period of 10 d. The semen evaluation was performed for each of the four treatments every other day. Results showed that the sperm concentration of spermatozoa affected the duration of storage based on the sperm motility percentage, viability and morphology of spermatozoa. The extended goat semen with sperm concentration of 25 and 50 million sperm/mL is optimal for storage within 6 d that gave satisfactory percentage motile, viable and morphologically normal spermatozoa.     

Monitoring distances travelled by horses using GPS tracking collars

Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.     

Unusual osteochondral lesions of the talus in a horse

A 2-year-old Thoroughbred gelding was evaluated for a grade 3 out of 5 unilateral hind limb lameness. Flexion of the right hock and stifle joints (spavin test) exacerbated the lameness. Response to intra-articular and perineural anaesthesia isolated the source of lameness to the tarsocrural area, despite an absence of tarsocrural joint effusion. Routine radiographic examination of the hock did not reveal any significant abnormalities. Skeletal nuclear scintigraphic evaluation revealed a focal region of increased bone activity in the proximal medial trochlear ridge of the talus. Flexed lateromedial radiographic views identified three discrete semicircular lytic lesions at the proximal articular margin of the medial trochlear ridge of the talus. Conservative management of the lesions was associated with a successful return to racing. The location and appearance of the osteochondral lesions of this report have not been previously reported and may be a manifestation of developmental orthopaedic disease and abnormal endochondral ossification. Nuclear scintigraphy and flexed lateromedial radiographic views facilitated identification of the lesions. This radiographic view is recommended when lameness is isolated to the tarsocrural joint and standard radio-graphic projections fail to identify a cause.