Compensatory growth,plasma hormones and metabolites in juvenile Siberian sturgeon (Acipenser baerii,Brandt 1869) subjected to fasting and re‐feeding

A 7‐week study was conducted to investigate the effect of different fasting and re‐feeding regimes on compensatory growth and some physiological parameters of juvenile Siberian sturgeon (Acipenser baerii). Fish (46.5 ± 0.5 g) were fed on a diet (containing 450 g/kg crude protein and 20 MJ/kg digestible energy) according to four feeding regimes in triplicate including: control group (C, fed everyday), W1 (2 weeks of feeding followed by 1 week of fasting and 4 weeks of re‐feeding), W2 (1 week of feeding followed by 2 weeks of fasting and 4 weeks of re‐feeding) and W3 (3 weeks of fasting followed by 4 weeks of re‐feeding). The fasted groups including W1 (119.6 ± 2.1 g), W2 (118.0 ± 1.7 g) and W3 (108.5 ± 4.8) significantly lost their weights during fasting phase and did not attain the final weight of the C (137.3 ± 1.7 g) after re‐feeding phase. The re‐feeding phase increased the specific growth rate in the fasted groups compared to the C (p < .05). After the fasting phase, concentrations of T₃, T₄, glucose, total protein and triglyceride in plasma of fasted groups were decreased, but levels of total cholesterol, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase increased compared to the C. After re‐feeding phase, except for glucose level, all mentioned metabolites were restored in the plasma of W1 group, but total protein level and aspartate aminotransferase concentrations in plasma were not restored in W2 and W3 groups. Overall, our finding demonstrated 4 weeks of re‐feeding was too short to induce full compensatory growth in A. baerii juveniles.     

Dietary butyric acid improved growth,digestive enzyme activities and humoral immune parameters in Barramundi (Lates calcarifer)

A six‐week feeding trial was conducted to determine the effect of butyric acid (BA) inclusion in diet on performance of Barramundi (Lates calcarifer). Fish (12.0 ± 0.2 g) were fed with four experimental diets contained 0.0 (control), 2.5, 5.0 and 10.0 g BA/kg in triplicate. Fish fed on 5 and 10 g BA/kg diets had higher growth and total alkaline protease and lipase activities than the other treatments. Fillet protein content in BA‐supplemented groups was higher than the control. Liver catalase activity was highest in 2.5 g BA/kg group compared with the other groups. The values of liver superoxide dismutase activity and serum total protein concentration in 5 and 10 g BA/kg treatments were higher than those in the control (p < .05). Moreover, the highest and the lowest levels of serum lysozyme activity were noticed in the 10 g BA/kg and the control groups, respectively (p < .05). Also, the highest respiratory burst activity was observed in fish fed 5 g BA/kg feed. Supplementing diet with 2.5 or 5 g BA/kg resulted in higher serum haemolytic activity in fish compared with the other groups. The number of red and white blood cells increased in fish fed BA‐supplemented diets compared with the control (p < .05). In conclusion, the results of this study showed inclusion of BA at 5 g/kg diet in L. calcarifer juveniles improved growth and upgraded the general health condition by enhancing fish antioxidant enzyme activities and haemato‐immunological responses.     

Dietary organic acid salts mitigate plant protein induced inflammatory response and improve humoral immunity,antioxidative status and digestive enzyme activities in yellowfin seabream,Acanthopagrus latus

An eight‐week research was conducted to investigate the effects of single or combined administration of sodium propionate (Na‐P) and sodium acetate (Na‐A) on the performance of yellowfin seabream (Acanthopagrus latus) juveniles (6.5 ± 0.3 g). A plant protein (PP)‐rich diet was supplemented with sole or blends of organic acid salts (OAS) namely Na‐P and Na‐A to design six experimental feeds including control (without OAS), Na‐P5 (5 g/kg Na‐P), Na‐P10 (10 g/kg Na‐P), Na‐A5 (5 g/kg Na‐A), Na‐A10 (10 g/kg Na‐A) and Na‐P + A (5 g/kg Na‐P + 5 g/kg Na‐A). Except for Na‐A5 group, the other OAS‐supplemented treatments had higher growth and feed efficiency ratio than the control (p < .05). The inclusion of OAS in the experimental feeds pronouncedly enhanced plasma lysozyme and alternative complement pathway activities compared to the control. Furthermore, fish fed on the OAS‐supplemented diets had greater catalase and glutathione peroxidase activities in the liver than the control (p < .05). Total antioxidant capacity in the liver of fish fed on the OAS‐supplemented diet also was higher than the control. Fish fed on the OAS‐supplemented diets had higher pepsin, trypsin and lipase activities than the control. The insulin‐like growth factor 1 (IGF‐1) gene expression was remarkably down‐regulated in the liver of fish fed on the OAS‐supplemented diets compared to the control especially in groups fed on the Na‐P10 and Na‐A10 diets. The greatest IGF‐1 gene down‐regulation level in the gut was in fish fed on the Na‐P5 and Na‐P10 diets. The interleukine‐1β in the gut was remarkably up‐regulated in the control compared to the other groups (p < .05). The lactic acid bacterial colonies count in the gut of the control was lower than the OAS‐supplemented groups. Based on the findings of the present study, supplementing PP‐rich diets with 10 g/kg Na‐P or blends of Na‐P (5 g/kg) and Na‐A (5 g/kg) beneficially alleviated inflammatory responses and improved immune parameters and digestive capacity in yellowfin seabream juveniles.     

Pleistocene extinction of genyornis newtoni: human impact on australian megafauna

More than 85 percent of Australian terrestrial genera with a body mass exceeding 44 kilograms became extinct in the Late Pleistocene. Although most were marsupials, the list includes the large, flightless mihirung Genyornis newtoni. More than 700 dates onGenyornis eggshells from three different climate regions document the continuous presence of Genyornis from more than 100,000 years ago until their sudden disappearance 50,000 years ago, about the same time that humans arrived in Australia. Simultaneous extinction of Genyornis at all sites during an interval of modest climate change implies that human impact, not climate, was responsible.     

Killer whale predation on sea otters linking oceanic and nearshore ecosystems

After nearly a century of recovery from overhunting, sea otter populations are in abrupt decline over large areas of western Alaska. Increased killer whale predation is the likely cause of these declines. Elevated sea urchin density and the consequent deforestation of kelp beds in the nearshore community demonstrate that the otter's keystone role has been reduced or eliminated. This chain of interactions was probably initiated by anthropogenic changes in the offshore oceanic ecosystem.     

Effect of Feline Immunodeficiency Virus Infection on Toxoplasma gondii-specific Humoral and Cell-mediated Immune Responses of Cats with Serologic Evidence of Toxoplasmosis

Serum samples from 89 cats with serologic evidence of toxoplasmosis were identified by using an enzyme-linked immunosorbent assay (ELISA) that detected Toxoplasma gondii -specific immunoglobulin M (IgM) or T. gondii -specific immunoglobulin G (IgG). Concurrent feline immunodeficiency virus (FIV) infection was detected in 36 cats using an ELISA for detection of FIV-specific IgG. The majority of the cats in both the FIV-seropositive and FIV-seronegative groups were male and >5 years of age. FIV-seropositive cats were more likely to have T. gondii IgM titers without IgG ( P > 0.05) or any T. gondii IgM titer ( P > 0.05) than were FIV-seronegative cats. FIV-seronegative cats (1328) had a higher T. gondii IgG geometric mean titer than did FIV-seropositive cats (724) and were more likely to have T. gondii IgG titers 1:2048 than were FIV-seropositive cats ( P > 0.05). Cats with serologic evidence of both T. gondii and FIV infections had persistent T. gondii IgM titers for >12 weeks. Lymphoblast transformation in response to concanavalin A, T. gondii -specific intracellular antigens, and T. gondii -specific secretory antigens was compared in T. gondii seropositive and FIV-seronegative cats, cats with serologic evidence of T. gondii infection alone, and cats with serologic evidence of concurrent FIV and T. gondii infections. Lymphocytes from all but one cat in the FIV-seropositive group responded to concanavalin A. Whereas lymphocytes from FIV-seronegative cats with serologic evidence of toxoplasmosis responded to T. gondii -specific antigens, four of five of the FIV-seropositive cats with concurrent serologic evidence of toxoplasmosis did not.     

Seasonality of Reproduction in Mammals: Intimate Regulatory Mechanisms and Practical Implications

Farm mammals generally express seasonal variations in their production traits, thus inducing changing availability of fresh derived animal products (meat, milk and cheese) or performances (horses). This is due to a more or less marked seasonal birth distribution in sheep and goats, in horses but not cattle. Birth peak occurs at the end of winter-early spring, the most favourable period for the progeny to survive. Most species show seasonal variations in their ovulation frequency (presence or absence of ovulation), spermatogenic activity (from moderate decrease to complete absence of sperm production), gamete quality (variations in fertilization rates and embryo survival), and also sexual behaviour. The intimate mechanism involved is a complex combination of endogenous circannual rhythm driven and synchronized by light and melatonin. Profound and long-term neuroendocrine changes involving different neuromediator systems were described to play a role in these processes. In most species artificial photoperiodic treatments consisting of extra-light during natural short days (in sheep and goats and mares) or melatonin during long days (in sheep and goats) are extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres. Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non-invasive ones which fully respect animal welfare. Genetic selection could be one of the future ways to decrease seasonality in sheep and goats.     

Enriched Artemia with L-lysine and DL-methionine on growth performance,stress resistance,and fatty acid profile of Litopenaeus vannamei postlarvae

A 15-day study was conducted to evaluate the effect of enrichment of Artemia metanauplii with four different emulsions, including: (A) Easy-DHA Selco; (B) Easy-DHA Selco + L-lysine (4 g/L); (C) Easy-DHA Selco + DL-methionine (4 g/L); and (D) Easy-DHA Selco + L-lysine (2 g/L) + DL-methionine (2 g/L) on growth and stress resistance of white leg shrimp Litopenaeus vannamei larvae (from Mysis I to postlarvae12). It is noticed that shrimp PL in group B had the highest wet (36.1 ± 3.1 mg) and dry (1116.7 ± 60.0 µg) weights as well as stress resistance to fresh water (64.0 ± 5.5%).     

Reproductive performance of postpartum ewes treated with insulin or progesterone hormones in association with ram effect

The reproductive performance of postpartum Santa Inês (SI) and Morada Nova (MN) ewes treated with insulin or progesterone hormones in association with ram effect was evaluated. Ewes from SI (n = 69) and MN (n = 69) breeds were randomly allocated to three groups of each breed (T1—ram effect only; T2—ram effect + insulin; T3—ram effect + progesterone). Progesterone concentrations (ηg/ml; mean ± SD) before and after introduction of rams (n = 6) were 0.51 ± 0.22 and 3.78 ± 0.68 (T1), 0.65 ± 0.21 and 3.77 ± 0.78 (T2) and 0.52 ± 0.21 and 3.84 ± 0.84 (T3) in SI ewes and 0.74 ± 0.19 and 3.71 ± 0.56 (T1), 0.70 ± 0.21 and 3.79 ± 0.75 (T2) and 0.81 ± 0.14 and 3.87 ± 0.80 (T3) in MN ewes, respectively. Thus, lower progesterone concentrations were found before the introduction of rams (p < .05). After the introduction of rams, preovulatory peaks of LH (ηg/ml) occurred at 28 (T1), 44 (T2) and 48 (T3) hr in SI ewes and at 64 (T1), 40 (T2) and 44 (T3) hr in MN ewes. The mean number of ovulations was similar between groups (p > .05), was 1.3 ± 0.51 (T1), 1.5 ± 0.54 (T2) and 1.6 ± 0.51 (T3) in SI ewes and 1.3 ± 0.51 (T1), 1.6 ± 0.51 (T2) and 1.6 ± 0.51 (T3) in MN ewes. In conclusion, the ram effect alone is effective at inducing and synchronizing oestrus in sheep under postpartum anoestrus, irrespective of hormone treatments.