Effects of diets containing genistein and diadzein in a long-term study on sex steroid dynamics of goldfish (Carassius auratus).

The effect of long-term exposure of goldfish to dietary genistein and diadzein on the concentrations of plasma sex steroids (testosterone (T), 17ß-estradiol (E2)) and the gonadosomatic index (GSI) was assessed. The study was conducted on four groups for a period of 2 years, from the age of 20 weeks to first spawning. Four doses of genistein and diadzein were applied in the feed: genistein: 0 µg/g, diadzein: 0 µg/g (control group); genistein: 24.26 µg/g, diadzein: 21.7 µg/g (diet 1); genistein: 51.55 µg/g, diadzein: 46.13 µg/g (diet 2); and genistein: 75.83 µg/g, diadzein: 67.82 µg/g (diet 3). Throughout the experiment, there were no significant dose- or time-related effects of genistein and diadzein contents on the T level in both sexes. Furthermore, at the highest genistein and diadzein contents, there was an elevating plasma concentration of E2 at all sampling points (p < 0.05) and a time-related effect occurred (p < 0.05). Although the E2 concentrations in the plasma of female, throughout the experiment, were higher than in males, at the last sampling, the plasma concentrations of E2 reduced among females and became lower than that in males. The effects of isoflavone content were found on GSI of females at the fourth and fifth sampling among the treatments. Isoflavone contents also affect GSI of males at the second, fourth and the last sampling. Our findings suggest that overall genistein and diadzein exposure in early life stages can cause alterations in the reproductive organs and influence sex steroidogenesis.

The first application of a new polysaccharide from Acanthophyllum bracteatum for the health improvement of Atlantic salmon exposed to mercury chloride.

Polysaccharides are biopolymers that play key roles as therapeutic agents. The current study examined the efficiency of a polysaccharide newly derived from a plant resource for detection of sub-acute mercury (Hg) exposure on blood characteristics of Atlantic salmon. The polysaccharide was extracted from the roots of Acanthophyllum bracteatum, and the Atlantic salmon were divided into three groups and placed in fiberglass tanks: one with no Hg as a control, one filled with 60 µg l(-1) of Hg solution, and one with 60 µg l(-1) Hg solution plus 1% weight/weight (w/w) of polysaccharide, which had been added 24 hours before the addition of Hg solution. Serum hematological and biochemical parameters were analysed. Results of the study showed that the blood factors were significantly adjusted in the group that had been exposed to the polysaccharide and Hg compared to the group that had been exposed only to Hg. The polysaccharide had an adjustment effect on lymphocytes, granulocytes, red blood cells (RBCs), Hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), protein, chlorine (Cl), sodium (Na), and glucose. It did not have a significant effect on hematocrit (Ht), mean corpuscular hemoglobin concentration (MCHC), potassium (K), and monocytes. Finally, the results confirmed that the new polysaccharide has useful effects on the host, possibly acting as a probiotic by selectively motivating the activity of some useful bacteria, which can improve the host health. This is the first report on application of this polysaccharide for the health improvement of Atlantic salmon exposed to mercury chloride.

Effects of replacing fish meal by soybean meal along with supplementing phosphorus and magnesium in diet on growth performance of Persian sturgeon, Acipenser persicus.

Looking for replacing fish meal by cheaper and more sustainable protein sources is essential for reducing the cost of fish feeds. Soybean meal is a suitable alternative protein sources for carnivorous fish such as Persian sturgeon, Acipenser persicus. However, it contains antinutritional factors that may affect bioavailability of minerals and lead in reduced growth. Achieving a cost-effective diet that does not have negative effects on growth is the goal of aquaculture programs. A 10-week experiment was conducted with Persian sturgeon (352.07 ± 5.51 g) to determine the combined effects of phosphorous (SP), magnesium and phosphorous (SPMg), phytase (SF), phytase and magnesium (SFMg), phosphorous and phytase (SPF), phosphorous, magnesium and phytase (SPMgF) on weight gain, feed efficiency, specific growth rate, and condition factor. A control diet was prepared with fish meal as a control group. Inclusion of P, Mg, and phytase contents within soybean diets did not improve feed efficiency, and still, the control diet containing fish meal showed better weight gain and feed efficiency. Among soybean meal groups, feed efficiency and specific growth rate were significantly improved for fish fed the diet containing just phytase (SF) and both phytase and phosphorus (P ≤ 0.05). It was true for specific growth rate and condition factor. Phytase significantly enhanced growth whether included with or without phosphorous. This study showed that fish meal is more sufficient for Persian sturgeon, and soybean meal could be partly an alternative protein source if phosphorous supplied for fish by incorporation with microbial phytase or phosphorous.

Reproductive impairment and endocrine disruption in goldfish by feeding diets containing soybean meal.

A long-term feeding experiment was conducted to investigate the inclusion of soybean meal in diets for goldfish (Carassius auratus) on fish reproduction. In the present study, 20 weeks after hatching, goldfish with an initial average weight of 2±0.03g (mean±SD) were divided into 12 groups (three tanks per dietary treatment) and fed 400gkg(-1) crude protein diets. The four experimental diets were as follows: diet 1, fish meal (FM); diet 2, 35% soybean meal (SBM35%); diet 3, 65% soybean meal (SBM65%); diet 4, 100% soybean meal (SBM100%). After feeding with experimental diets, the impact on reproduction was investigated. In both males and females, the plasma testosterone (T) was significantly decreased, while 17ß-estradiol (E2) levels were significantly increased. Levels of 17α, hydroxyprogesterone. (17-OH-P) did not differ as a result of soybean meal feeding in either males or females. The average number of eggs spawned and sperm quality were reduced on feeding with soybean inclusion. Histological examination showed impact on oocyte maturation progress and spermatogenesis process in female and male fish, respectively. In addition, feeding goldfish with soybean meal until maturation caused reduction in fertilization and hatching rates in parallel to increasing soybean meal inclusion. The results demonstrated that inclusion of soybean meal might cause sex hormone biosynthesis disruption and reproductive impairments in fish, ultimately decreased fertilization as well as hatching rates in the offspring.