Juveniles and larvae of eleven fish species collected from three countries of the Arabian Gulf and the Arabian Sea

The finding of larval and juvenile specimens from the Omani coast of the Arabian Sea and the Arabian Gulf waters of Saudi Arabia and Iraq is reported for the first time. Based on available information, one larva was a leptocephalus, Conger sp. (family Congridae) and one larva of an acronurus stage belonging to the genus Acanthurus (family Acanthuridae). Also juveniles of the following families are included in the present study: Clupeidae – Tenualosa ilisha (Hamilton, 1822) and Nematalosa sp.; Dactylopteridae – Dactyloptena orientalis (Cuvier, 1829); Gobiidae – Acentrogobius sp.; Bothidae – Arnoglossus aspilos (Bleeker, 1851); Scatophagidae – Scatophagus argus (Linnaeus, 1766); Sparidae – Acanthopagrus arabicus Iwatsuki, 2013 and Sparidentex hasta (Valenciennes, 1830); Tetraodontidae – Lagocephalus sp. The discovery of the barred rather than spotted juveniles of S. argus collected from pure freshwater environment of the Shatt al-Arab River, Basrah, Iraq was remarkable; it raises questions whether there is more than one species within the nominal S. argus. For both larvae and juveniles of bothid flounders, the olfactory organ is a useful character for the examination of the developmental stage of the metamorphosing specimens. The occurrence of the different early life history stages of fishes from the three Arabian countries shows the needs them to be studied further so that inferences about the areas and periods of spawning and development of these fishes can be made more accurately.

Effects of a single-phase fasting period and subsequent re-feeding on compensatory growth, digestive enzyme activities, and antioxidant capacity of Sobaity (Sparidentex hasta) and Yellowfin seabream (Acanthopagrus latus)

An eight-week research was carried out to examine the influence of fasting (FA) and refeeding (RF) episodes on the compensatory growth responses (CGR) in sobaity (Sparidentex hasta, 10 g) and yellowfin seabreams (Acanthopagrus latus, 4.3 g) juveniles. Fish were fed with a commercial feed (contained 500 g kg−1 crude protein and 150 g kg−1 crude lipid) as following regimes: control (C, fish were fed three times every day), T1 (two weeks of feeding, one week of FA, and five weeks of RF), T2 (one week of feeding, two weeks of FA and five weeks of RF) and T3 (three weeks of FA and five weeks of RF). Two hundred and forty S. hasta juveniles were stocked into twelve 300-L tanks (20 fish tank−1), and 360 A. latus juveniles were allocated into other 12 tanks (30 fish tank−1). Each treatment was carried out in triplicates for each species, and each tank held only one of the species. The experiment was carried out for both species simultaneously. The weight and length of fish from the four groups were measured individually after the third week (after FA episode) and after eight weeks (after RF episode). After finishing the RF episode (eighth week), six fish of each tank were sacrificed with an overdose of 2-phenoxyethanol (1000 mg L−1), and the liver and the whole gut of the sacrificed fish were sampled, dissected, and then kept in a freezer (−80 °C) until further analyses. Survival rate was decreased in S. hasta juveniles with increasing the FA period mainly due to their cannibalistic behavior, which was triggered by starvation, but it was not affected in A. latus. The fasted groups in both species were significantly lost their weight after FA episodes. After five weeks of RF, S. hasta showed full compensatory growth response; meanwhile A. latus had a partial compensatory response (P<0.05). Hepatosomatic index value decreased after the FA period in both species, but it was restored to the normal level after RF phase. The activities of liver catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase were increased in T2 group in S. hasta, but liver antioxidant enzymes were not affected in A. latus. In both species, the amount of the lipid peroxidation was significantly increased in the liver of fish groups subjected to T2 or T3 compared to T1 and control groups (P < 0.05). Liver alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in S. hasta fasted for two weeks were higher than the other groups. The activities of trypsin, chymotrypsin, α-amylase, and lipase in S. hasta fasted for a week (T1) were higher than control. In addition, the activities of trypsin and chymotrypsin in A. latus fasted for two or three weeks were lower than C and T1 groups. The activity of ALP was increased with increasing FA period in both species. The findings of the present study showed that single-phase FA episodes reduce survival and induce oxidative stress in S. hasta juveniles; meanwhile A. latus juveniles did not show complete compensatory growth after RF episode.

Effects of Single and Combined Supplementation of Dietary Probiotic with Bovine Lactoferrin and Xylooligosaccharide on Hemato-Immunological and Digestive Enzymes of Silvery-Black Porgy (Sparidentex hasta) Fingerlings

The aim of this study was to evaluate the effects of different levels of dietary Lactobacillus plantarum as probiotic (Pro) with bovine lactoferrin (LF) and xylooligosacharide (XOS) on growth performance, hemato-immune response, body composition, digestive enzymes activity and expression of immune-related and growth-related genes of sobaity (Sparidentex hasta) for 8 weeks. Fish were fed with feed including: control diet (no LF, XOS and pro inclusion), diet 1 (400 mg kg−1 LF + 5000 mg kg−1 XOS), diet 2 (400 mg kg−1 LF + 10000 mg kg −1 XOS), diet 3 (400 mg kg−1 LF + 1 × 106 gr−1 Pro (L. plantarum)), diet 4 (800 mg kg−1 LF + 5000 mg kg −1 XOS), diet 5 (800 mg kg−1 LF + 10000 mg kg−1 XOS), diet 6 (800 mg kg−1 LF + 1 × 106 gr−1 Pro (L. plantarum)). Growth performance, hematological parameters (except for white blood cell counts), body composition and immune-related gene expression were not affected by different experimental groups (p>0.05). Nonetheless, non-specific immune response (except for total immunoglobulin) and growth-related gene expression of treatments and control group significantly varied (P<0.05). Digestive enzymes activity including total protease and amylase increased by supplementing diets with different combinations of immunostimulants (P<0.05). Our results suggest that diets supplemented with selected levels of LF, XOS and L. plantarum could not improve growth performance, body composition and hemato-immune response, but improved digestive enzyme activities in S. hasta fingerlings.