Impact of brining and drying processes on the nutritive value of tambaqui fish (Colossoma macropomum)

Preservation of fish as diet ingredient is challenging in many tropical regions due to poor socioeconomic conditions and lack of freezing facilities. So, alternative preservation techniques could be viable to address the issue. The present study evaluated the effect of brine salting (15% w/v) prior to drying at different temperatures on the nutrient profiles of tambaqui fish (Colossoma macropomum). Whole fish samples (n = 48; 792 ± 16 g; 8 months old) were grouped into two as brine-salted and non-salted, and treated at seven different drying temperatures of 30, 35, 40, 45, 50, 55 and 60°C for a period of 23 h each. To evaluate the impact of Maillard reaction, reactive lysine was also quantified. Drying temperature had no effect on the evaluated macro- and micro-nutrients of tambaqui fish (P > 0.05) while brining reduced the overall protein concentration by 6% (58.8 to 55.4 g/100 g DM; P = 0.004). Brining significantly reduced many amino acids: taurine by 56% (7.1 to 3.1 g/kg; P < 0.001), methionine 17% (14.7 to 12.1 g/kg; P < 0.001), cysteine 11% (5.1 to 4.4 g/kg, P = 0.016), and reactive lysine 11% (52.0 to 46.4 g/kg; P = 0.004). However, alanine, arginine, and serine were not affected by brining (P > 0.05). Brining also reduced the concentrations of Se by 14% (149 to 128 μg/kg DM; P = 0.020), iodine 38% (604 to 373 μg/kg DM; P = 0.020), K 42% (9.71 to 5.61 g/kg DM; P < 0.001) and Mg 18% (1.32 to 1.10 g/kg DM; P = < 0.001) versus an anticipated vast increase in Na by 744% (2.70 to 22.90 g/kg DM; P < 0.001) and ash 28% (12.4 to 16.0 g/100g DM; P < 0.001) concentration. Neither brining nor drying temperature induced changes in % lysine reactivity and fat content of tambaqui fish (P > 0.05). Agreeably, results of multivariate analysis showed a negative association between brining, Na, and ash on one side of the component and most other nutrients on the other component. In conclusion, drying without brining may better preserve the nutritive value of tambaqui fish. However, as a practical remark to the industry sector, it is recommended that the final product may further evaluated for any pathogen of economic or public health importance.

An in vivo duck hepatitis B virus model recapitulates key aspects of nucleic acid polymer treatment outcomes in chronic hepatitis B patients

Nucleic acid polymers (NAPs) are an attractive treatment modality for chronic hepatitis B (CHB), with REP2139 and REP2165 having shown efficacy in CHB patients. A subset of patients achieve functional cure, whereas the others exhibit a moderate response or are non-responders. NAP efficacy has been difficult to recapitulate in animal models, with the duck hepatitis B virus (DHBV) model showing some promise but remaining underexplored for NAP efficacy testing. Here we report on an optimized in vivo DHBV duck model and explore several characteristics of NAP treatment. REP2139 was efficacious in reducing DHBV DNA and DHBsAg levels in approximately half of the treated ducks, whether administered intraperitoneally or subcutaneously. Intrahepatic or serum NAP concentrations did not correlate with efficacy, nor did the appearance of anti-DHBsAg antibodies. Furthermore, NAP efficacy was only observed in experimentally infected ducks, not in endogenously infected ducks (vertical transmission). REP2139 add-on to entecavir treatment induced a deeper and more sustained virological response compared to entecavir monotherapy. Destabilized REP2165 showed a different activity profile with a more homogenous antiviral response followed by a faster rebound. In conclusion, subcutaneous administration of NAPs in the DHBV duck model provides a useful tool for in vivo evaluation of NAPs. It recapitulates many aspects of this class of compound's efficacy in CHB patients, most notably the clear division between responders and non-responders.

Substrate colour guides turquoise killifish's (Nothobranchius furzeri) choice of preferred spawning habitat

Turquoise killifish (Nothobranchius furzeri) is a promising new model species used in biomedical and ecological laboratory experiments, and should be kept under optimal conditions to ensure fish welfare and the quality of science. While the popularity of this model species is rapidly increasing, we need to improve our understanding of how the species interacts with its environment to optimize its husbandry. Specifically, turquoise killifish are substrate spawners that bury their eggs in the sediment, which can be accommodated under captive conditions, but it is not yet known whether or not turquoise killifish have a preference for a specific sediment colour. Here, we performed a laboratory experiment in which fish could choose between white, orange and black sand for spawning, colours which are relevant in both laboratory and field conditions. We assessed their preference in the context of single breeding pairs, as well as in a social group setting. Additionally, we also assessed the preference of individuals for a white versus black background in a nonmating context. Single breeding pairs deposited over 3.5 times more eggs in black compared to orange or white sand. Similarly, fish in social groups deposited over 3.5 times more eggs in black compared to orange sand, which in turn was over two times higher than that in white sand. Fish showed a slight preference for the black compared to the white zone in a nonmating context, but this did not correlate with substrate choice during the spawning tests. The results suggest that turquoise killifish select their preferred spawning location based on the colour of the substrate. These findings contribute to our understanding of the species' biology and can help to guide good welfare and scientific practice.

Management factors resulting in a severe reduction in feed intake-induced spiking mortality syndrome in young broiler chicks

This study aimed to induce spiking mortality syndrome (SMS) in 10-day-old broiler chicks by changing feed particle size (crumble feed to pellet feed) and/or feed source location (from a small feeder at the pen's center to a large feeder at the front of the pen), followed by full day feed deprivation of all broiler chicks on day 11. In total, 396-day-old male Ross 308 broiler chicks were randomly assigned to 4 treatments (Con: without change in feed particle size and feed source location; Par: changing crumble feed to pellet feed on day 10; Loc: changing feed source location on day 10; LocPar: changing both feed particle size and feed source location on day 10). Each treatment consisted of 9 replicate pens with 11 chicks each. Each treatment was applied at 09:00 on days 10 and 11. On both days, chicks with SMS were identified based on clinical symptoms (down in sternal or lateral recumbency, hyperventilation). Plasma glucose, 3, 3′, 5-triiodothyronine (T₃), thyroxine (T₄) concentrations, insulin, and liver glycogen concentrations of chicks without (normal) and with SMS were measured. Proportional organ and digestive tract including content weights were recorded. Broiler behavior was assessed hourly from 08:30 to 17:30 on day 10. On day 10, the Par, Loc, and LocPar groups spent significantly less time feeding and more time lying down compared with the Con group. On days 10 and 11, SMS clinical signs were observed around 2.5 to 3.5 h after the initiation of treatments, and the Loc group had the most SMS morbidity level. Spiking mortality syndrome chicks had significantly less digestive tract contents compared with Normal chicks on day 10. Spiking mortality syndrome was induced successfully with the treatments, according to their significantly reduced plasma glucose, insulin, T3 and T4 concentrations as well as liver glycogen content. A significant correlation between plasma glucose and liver glycogen was observed in SMS chicks. In conclusion, management factors inducing the reduction or absence of feed intake on day 10 or day 11 can trigger the occurrence of SMS in young broiler chicks.

[Psychosis in a patient with Prader-Willi syndrome]

Prader-Willi syndrome (pws) is a genetic disorder characterised by specific physical and behavioural abnormalities. Recent studies indicate that patients suffering from this syndrome have an increased risk of psychiatric disorders, including psychosis. We describe the development and the psychiatric condition of a 31-year-old patient with pws who had a first psychotic episode at age 14 and subsequently experienced a highly variable course of recovery and relapse.

[Risk factors and development course of conduct disorder in girls; a review]

BACKGROUND

So far there have been relatively few studies of conduct disorder in girls. It is very important that professionals engaged in preventing and treating this disorder have a sound knowledge of the risk factors involved and of the developmental course of the disorder.

AIM

To provide an overview of what is known about the risk factors and about the way in which conduct disorder develops in girls.

METHOD

We searched the Eric, PubMed and Medline databases for articles on conduct disorder in girls. We reviewed 41 studies and we summarised the results.

RESULTS

Several risk factors contribute to the development of conduct disorder in girls. Just like boys, girls too can display the life-course-persistent pathway of antisocial behavior. Such girls are often associated with serious risk factors. Those with serious forms of antisocial behaviour have an increased risk of experiencing adjustment problems in later life.

CONCLUSION

Future research in this area will have to concentrate on the creation of adequate prevention and treatment programs.