Partial replacement of fish oil by soybean oil on lipid distribution and liver histology in European sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss) juveniles

A 12-week feeding trial was conducted to evaluate the effects of fish oil replacement by soybean oil, on lipid distribution and liver histology of two commercially important finfish species: rainbow trout (Oncorhynchus mykiss) and European sea bass (Dicentrarchus labrax). Sea bass (16.2 +/- 0.5 g; mean +/- SD) and rainbow trout (52.1 +/- 0.5 g) juveniles were fed one of three isonitrogenous (500 g kg(-1) CP) and isoenergetic (19 kJ g(-1)) diets, containing 0% (control, diet A), 25% (diet B) and 50% (diet C) soybean oil. At the end of the experiment, lipid deposition was evaluated in muscle, liver and viscera. Cholesterol and triglycerides levels were also determined in plasma. Tissue total, neutral and polar lipid composition (g kg(-1) total lipids) showed no significant differences within species, regardless the dietary treatment. The same trend was observed for plasma parameters (P > 0.05). Viscera were the preferential tissue of lipid deposition, with 252-276 and 469-513 g kg(-1) total lipid content in trout and sea bass, respectively. Dietary fish oil replacement had no effect on either hepatic lipid droplets accumulation or degree and pattern of vacuolization in the observed liver sections. These data suggest that both sea bass and trout can be fed diets containing up to 50% soybean oil without adverse effects on tissue lipid composition or liver histology

Hyperplastic and hypertrophic growth of lateral muscle in blackspot seabream Pagellus bogaraveo from hatching to juvenile

To understand better the growth mechanisms in the economically important fish Pagellus bogaraveo, in terms of muscle fibre hyperplasia v. hypertrophy, the lateral muscle of this fish was studied morphometrically from hatching to juvenile comparing rostral and caudal locations. Fish were sampled at 0, 5, 23, 40, 70, 100, 140 and 180 days. Fibre types were first identified by succinate dehydrogenase (SDH) and immunostaining with a polyclonal antibody against fish slow myosin (4-96). Morphometric variables were then measured in transverse body sections, at both post-opercular and post-anal locations, to estimate the following variables: total muscle area [A (muscle)], total fibre number [N (fibres)], fibre number per unit area of muscle [N-A (fibres, muscle)] and cross-sectional fibre area [a (fibres)] of the two main muscle fibre types (white and red). Overall, growth throughout the various stages resulted from increases both in the number and in the size of muscle fibres, paralleled by an expansion of the [A (muscle)]. Nonetheless, that increase was not significant between 0-5 days on one hand and 100-140 days, on the other hand. On the contrary, the [N-A (fibres, muscle)] declined as the body length increased. Analysis of the muscle growth kinetics suggested that, within the important time frame studied, hyperplasia gave the main relative contribution to the increase of white muscle [A (white muscle)], whereas red muscle [A (red muscle)] mainly grew by hypertrophy, with both phenomena occurring at a faster pace posteriorly in the body. Finally, when comparing rostral and caudal locations, a greater [N (fibres)] and [A (muscle)] of the posterior white and red fibres were the consistent features. It was also observed that the proportion of the cross-sectional area of the myotomal muscle comprised of white muscle was greater in the anterior part of the fish

Expression of the myosin light chains 1, 2 and 3 in the muscle of blackspot seabream (Pagellus bogaraveo, Brunnich), during development

Previous studies on the histochemistry and immunoreactivity of fibres in lateral muscle of blackspot seabream indicated that there is a developmental transition in the composition of myofibnllar proteins, which presumably reflects changes in contractile function as the fish grows We hypothesize that the phenomenon underscores age and spatial differences in the expression of myosin light chains (MLC), not studied yet in this species In this study, we examined selected stages in the post-hatching development of the muscle of blackspot seabream hatching (0 days), mouth opening (5 days), weaning (40 days) and juveniles (70 days) The spatial expression of embryonic MLC 1 (MLC1), 2 (MLC2) and 3 (MLC3) was studied by in situ hybndization Overall, MLC expression patterns were overlapping and restricted to the fast muscle At hatching and mouth opening, all MLC types were highly expressed throughout the musculature in fast muscle The expression levels in fast muscle remained high until weaning when germinal zones appeared on the dorsal and ventral areas The germinal zones were characterized by small-diameter fast fibres with high levels of MLC expression This pattern persisted up to day 70, when the germinal zones disappeared and expression of MLCs was observed only in the smaller cells of the fast muscle mosaic These results support our hypothesis and, together with previous imuno-and histochemistry results, allow a better understanding of the mechanism of muscle differentiation and growth in fish beyond larval stages, and form- the basis for further comparative and experimental studies with this economically relevant specie

Compression Stockings Used During Two Soccer Matches Improve Perceived Muscle Soreness and High-Intensity Performance.

Gimenes, SV, Marocolo, M, Pavin, LN, Pagoto Spigolon, LM, Neto, OB, Côrrea da Silva, BV, Duffield, R, and Ribeiro da Mota, G. Compression stockings used during two soccer matches improve perceived muscle soreness and high-intensity performance. J Strength Cond Res XX(X): 000-000, 2018-Evidence on the use of compression stockings (CS) during soccer matches is limited. Thus, we evaluated the acute effects of CS on match-based physical performance indicators and perceptual responses during 2 consecutive soccer matches with 72-hour recovery. Twenty outfield players were randomly allocated to the CS group (20-30 mm Hg) or control group (non-CS) and performed 2 matches (5 players using CS or regular socks per team/match). Match loads {rating of perceived exertion × minutes; CS ∼830 vs. control 843 (arbitrary units [AU])} and heart rate (HR) responses (both CS and control ∼86% HRpeak) did not differ (p > 0.05) between CS and control groups. Although total distance covered did not differ (p > 0.05) between groups, CS increased distances (effect size [ES] = 0.9-1.32) in higher-speed zones (>19 km·h CS ∼550 m vs. control ∼373 m) alongside an increased number of accelerations (-50.0 to -3.0 m·s) than control (CS: 33.7 ± 11.2 vs. control: 23.8 ± 7.9; p = 0.003; ES = 1.04). Perceived recovery did not differ (p > 0.05) between groups for either match but was worse in the second match for both groups. Perceived muscle soreness increased in control after match 2 (from 3.1 ± 1.9 to 6.3 ± 1.6 AU; p < 0.0010) but did not in CS (from 2.8 ± 1.4 to 4.1 ± 1.9 AU; p = 0.6275; ES = 1.24 CS vs. control after match). Accordingly, CS use during 2 soccer matches with 72-hour recovery reduces perceived muscle soreness in the second match and increases higher-speed match running performance

Transcriptome changes in newborn goats' skeletal muscle as a result of maternal feed restriction at different stages of gestation

We investigated how feed restriction at 50% of maintenance requirements during different stages of gestation affects the transcriptome of newborn goats' skeletal muscle. Fourteen pregnant dams were randomly assigned into one of the following dietary treatments: animals fed at 50% of maintenance requirement from 8-84 d of gestation and then fed at 100% of maintenance requirement from day 85 of gestation to parturition (RM, n = 6), and animals fed at 100% of maintenance requirement from 8-84 d of gestation and then fed at 50% of maintenance requirement from day 85 of gestation to parturition (MR, n = 8). At birth, samples of offspring's Longissimus muscle were collected for total RNA extraction and sequencing. Our data showed 66 differentially expressed (DE) genes (FDR &lt; 0.05). A total of 6 genes were upregulated and 60 downregulated (FDR &lt; 0.05) in the skeletal muscle of the newborns resulting from treatment RM compared with MR. Our results suggest that the DE genes upregulated in newborn goats' skeletal muscle from the RM group compared to MR, included genes related to satellite cells, and genes that indicates impaired insulin sensitivity and changes in the composition of intramuscular fat. The DE genes upregulated in newborn goats' skeletal muscle from the MR group compared to RM, are also related to impaired insulin sensitivity, as well as a predominantly oxidative metabolism and cellular oxidative stress. However, protective mechanisms against insulin sensitivity and oxidative stress may have been augmented in the skeletal muscle of offspring from MR treatment compared to RM, in order to maintain cellular homeostasis