Optimizing the co-feeding strategy of Persian sturgeon (Acipenser persicus) larvae using Artemia nauplii and formulated diet

High mortality and labor costs are associated with first-feeding sturgeon culture, particularly during the period of dietary transition from live to formulated feed. Therefore we investigated the effects of various feeding treatments on the survival and growth of the Persian sturgeon (Acipenser persicus) larvae during a 20-day culture period. Three replicate groups (250 fish/replicate) of first-feeding larvae were fed according to four main feeding regimes: (1) live food (live nauplii of brine shrimp Artemia urmiana); (2) indirect transition (5 days live food followed by gradual transition to formulated diet); (3) direct transition (using different combinations of live and formulated diet from the start feeding onwards); (4) formulated feed (FD) from the start feeding. Results indicated that growth and survival were higher in the indirect transition feeding regime than in other regimes. Based on our study, co-feeding of A. persicus should start five days after prior feeding with live food

The effects of zinc-enriched Saccharomyces cerevisiae on the growth and mineral composition of marine rotifer, Brachionus plicatilis

Rotifers are important zooplankton in commercial finfish hatcheries. However, due to the limited variety of food available, zinc content of cultured rotifers in artificial environments may not meet the requirements of fish larval. It has been reported that direct addition of soluble zinc to culture media was not effective on the zinc content of rotifer. Thus, in this study, the effect of zinc-enriched Saccharomyces cerevisiae was investigated on the growth and mineral composition of rotifer, Brachionus plicatilis. Four different food treatments, including (1) yeast without enrichment (control), (2) yeast containing 21.23 mg g-1 of zinc, (3) yeast containing 56.25 mg g-1 of zinc, and (4) yeast containing 132.93 mg g-1 of zinc, were used to produce rotifer for a period of 10 days. Afterwards, specific growth rate (SGR), the total number of rotifers, total eggs attached to rotifers, and the total number of eggs were measured. Finally, the mineral composition of rotifer in different treatments was analyzed. The findings revealed that yeast enriched with 56.25 mg g-1 of zinc significantly improved the growth of rotifers. The maximum number of rotifers (274 ind ml-1), total eggs attached to rotifers (29.3 number ml-1), and the total number of eggs (36 number ml-1) were found in the third treatment. The highest zinc content was observed in the fourth treatment (about 822.5 μg g-1 of rotifers). The maximum values of Fe (13.84 μg g-1 of rotifers) and Mn (15.22 μg g-1 of rotifer) were related to the treatment 4 and control, respectively. However, the amount of Cu did not significantly differ among the treatments. In conclusion, this study found that zinc-enriched yeast improved the growth, reproduction, and body composition of B. plicatilis

On the occurrence of Lepidurus apus (Linnaeus, 1758) (Crustacea, Notostraca) from Iran

The occurrence of Lepidurus apus in Iran is reported for the first time. this species was found in Aigher goli located in the mountains area, east Azerbaijan province (North east, Iran). details on biogeography, ecology and morphology of this species are provided

Short-term enrichment of microalgae with inorganic selenium and zinc and their effects on the mineral composition of microalgae and marine rotifer Brachionus plicatilis

Rotifers are widely used as a live prey for finfish larvae, although their content in minerals such as selenium and zinc is lower than in fish. In the present study, mixed microalgae (i.e., Isochrysis aff. galbana and Nannochloropsis oculata) were enriched with different amounts of Se and Zn either alone (45, 90, and 135 mg L−1 of Zn, 60, 120, and 180 mg L−1 of Se) or mixed (22.5, 45, and 90 mg Zn L−1 and 30, 60, and 120 mg Se L−1). The content of minerals in the microalgae was analysed after 1 and 3 h enrichment and their effect on the growth and mineral composition of the rotifer. Based on the results, 1 h enrichment time and 90 and 120 mg L−1 of Zn and Se, respectively, resulted in the highest amount of Se and Zn in enriched microalgae. The maximum Zn content was detected in the rotifers fed 90 mg L−1 Zn and 90 mg L−1 Zn +120 mg L−1 of Se, but the maximum Se was observed in rotifers fed with 120 and 180 mg L−1 Se. Thus, Se- and Zn-enriched rotifers can be used as a mineral delivery method to cover marine fish larvae nutritional requirements.info:eu-repo/semantics/acceptedVersio

Improving co‐feeding strategies for Neotropical green terror cichlid (Aequidens rivulatus) larvae with lecithin‐enriched Artemia franciscana nauplii: Effects on survival, growth performance and body composition

The effects of feeding on a commercial diet and lecithin‐enriched (EN) Artemia franciscana nauplii for improving co‐feeding strategies of Neotropical green terror cichlid (Aequidens rivulatus) larvae were conducted. For this purpose, eight groups of fish in triplicates were assigned with two different diets (unenriched Artemia [UN] and EN Artemia) and four feeding regimes (1, 5, 10 and 25 days feeding with UN and EN diets and then a 10% daily replacement Artemia nauplii with commercial diet). The crude lipid (21.4%) and total polar lipid (12.96% of total crud lipid) levels significantly increased in enriched Artemia nauplii (p < 0.05). The highest amount of saturated fatty acids (SFA) were in enriched and UN Artemia nauplii (41.74% and 49.64% respectively) but the highest level of monounsaturated fatty acids (MUFA) (25.69%) and polyunsaturated fatty acids (PUFA) (49.11%) were obtained in commercial diet. Growth performance of fish fed 10 EN and 5 EN had significantly higher values of total weight (120.67, 120.31 mg), %WG (584.48, 580.50%) and SGR (7.69, 7.67%) respectively (p < 0.05). Nevertheless, fish fed 25 EN had significantly higher FCE (190.4%), PER (3.95) and NPU (202.5), in comparison with other groups. In terms of body composition, the EN Artemia nauplii led to increased lipid contents in 25 EN, 10 EN and 5 EN treatments. In conclusion, the results of this study revealed that feeding regimes of 10 EN and 5 EN could improves survival and growth performance of Neotropical green terror cichlid, A. rivulatus larvae.info:eu-repo/semantics/acceptedVersio

Effects of temperature on survival, growth, reproductive and life span characteristics of Branchinecta orientalis G. O. Sars, 1901 (Branchipoda, Anostraca) from Iran

Branchinecta orientalis G. O. Sars, 1901 is a common inhabitant of seasonal water catchments in the northwest of Iran. Hatching, growth, survival, and reproductive characteristics of this species were studied at different temperatures in the laboratory. The Cumulative Hatching Success was significantly higher for specimens cultured at 21 degrees C (85.27 +/- 12.21%) compared to those hatched at 12, 15 and 27 degrees C (P < 0.05). Hatching started on the same day (48.00 h after inundation) at temperatures of 21, 24 and 27 degrees C), whereas this took more time at lower temperatures, slowest at 12 degrees C (126.00 +/- 0.58 h after inundation). The initial hatching fraction was the highest at 21 degrees C (44.60 +/- 18.69%) and lowest at 12 degrees C (9.10 +/- 8.28%). Total length was significantly longer at high temperatures, 12.38 +/- 0.71 mm at 27 degrees C, compared to 4.07 +/- 0.42 mm at 12 degrees C on day 15. Nevertheless, contrasting results were obtained for survival, being the lowest at 27 degrees C (22 +/- 4.00%) and highest at 12 degrees C (93.07 +/- 2.08%) on day 15 of growth. The animals reached sexual maturity significantly faster at 27 degrees C (9.38 +/- 1.09 days) compared to all other treatments. A significantly longer life span was detected at 12 and 15 degrees C (63 days), and the higher cyst production at 18 degrees C, compared to other experimental conditions (P < 0.05)

Lecithin-enriched Artemia combined with inert diet and its effects on reproduction and digestive enzymes of Aequidens rivulatus

The present study investigated the effects of soybean lecithin bioencapsulated in adult Artemia franciscana and unenriched Artemia in combination with an inert diet on digestive enzymes activity and reproductive performance in Aequidens rivulatus (green terror cichlid). Eight hundred and ten fish (3.1 ± 0.2 g) were randomly allotted into glass tank (80 L) and assigned to ten dietary treatments with 5 different levels (0, 25, 50, 75, and 100%) of either lecithin-enriched Artemia (EA) or unenriched Artemia (UA) over a period of 90 days. The amount of total polar lipid increased from 39.2% in the unenriched Artemia to 43.7% in the lecithin-enriched Artemia (P < .05). The fish fed with 50% EA had higher total weight, and total length compared with other groups (P < .05). The peculiar functions of total alkaline proteases, α-amylase, and lipase in green terror increased in the groups fed with lecithin-enriched Artemia, compared to the un-enriched groups (P < .05). The highest total alkaline proteases activity was observed in the fish fed with 75% EA treatment. In comparison to the other groups, fish fed 100 and 0% levels of Artemia replacement had significantly highest and lowest α-amylase activity values, respectively. Concerning reproductive performance, the highest average fecundity, egg diameter, egg weight, fertilization, hatching, and larval survival rates, as well as the lowest time between two spawning episodes, were obtained in fish fed 50% EA. In conclusion, this feeding strategy is advisable for a proper nutritional management of broodfish of green terror cichlid.info:eu-repo/semantics/acceptedVersio

Body shape changes during the early development of the Beluga (Huso huso)

Early body shape changes of beluga sturgeon were studied using landmark-based geometric morphometric approach to recognize its allometric growth pattern. Sampling was done from hatching up to 50 days post hatching (DPH). Left side of specimens were photographed using digital camera and nine landmark points were digitized on two-dimensional images. Total length (TI) was measured using the software ImageJ. To study of the body shape changes during early development, the mean procrustes distance between all specimens of same age, for all age groups, was calculated. The scores of relative warp analysis (RW) were used as descriptors for the variation in shape. RW analysis revealed a sharp body shape change during early ontogeny on 18 DPH. Growth trajectory was computed by plotting RW against TL. The inflection point of body shape corresponds to a TL of 23.3 mm (18 DPH). Results showed that ontogenetic shape changes encompassed a pre-inflection shape changes, which included the elongation of the head and tail regions i.e. positive allometric growth pattern and post-inflection shape changes, with a nearly isometric growth pattern

Dietary fatty acid profiling in plant protein‐rich diets affects the reproductive performance, egg fatty acid profile and haematological parameters in female rainbow trout (Oncorhynchus mykiss)

The influence of dietary fish oil (FO) substitution with blends of vegetal oils (VO: canola, linseed, olive, sunflower, corn and coconut oils) in plant protein‐rich diets on reproductive performance and fatty acid dynamics of embryos was evaluated in female rainbow trout (Oncorhynchus mykiss) brooders (1.8 ± 0.1 kg). Four diets were formulated in which 20% (FO80/VO20), 50% (FO50/VO50), 75% (FO25/VO75) and 100% (VO100) of FO were replaced by mixture of VO. The above‐mentioned diets were administered for a short period prior to spawning (3 months). Fish fed the VO100 had the lowest fertilization rate (81.3 ± 2.3), whereas brooders fed the FO80/VO20 diet had the lowest survival rates at eyed embryo stage (83.7 ± 1.6%) and hatching rate (79.9 ± 3.1%). The fatty acid dynamics of embryos were not only affected by embryonic developmental stages, but also they were influenced by the dietary fatty acid profile. Our study confirmed that using blends of different VO sources and FM residual fat in the FO25/VO75 for the short‐term period prior to spawning seemed to be a good strategy in terms of successful reproduction for sparing high levels of FM and FO in diet of O. mykiss brooders.info:eu-repo/semantics/acceptedVersio

Macronutrient Requirements of Silvery-Black Porgy (Sparidentex hasta): A Comparison with Other Farmed Sparid Species

Silvery-black porgy (Sparidentex hasta) is recognized as one of the most promising fish species for aquaculture diversification in the Persian Gulf and the Oman Sea regions. In this regard, S. hasta has received considerable attention, and nutritional studies focused on establishing the nutritional requirements for improving diet formulation have been conducted during recent years. Considering the results from different dose–response nutritional studies on macronutrient requirements conducted in this species, it can be concluded that diets containing ca. 48% crude protein, 15% crude lipid, 15% carbohydrates and 20 KJ g−1 gross energy are recommended for on-growing S. hasta juveniles. In addition, the optimum essential amino acid profile for this species (expressed as g 16 g N−1), should be approximately arginine 5.3, lysine 6.0, threonine 5.2, histidine 2.5, isoleucine 4.6, leucine 5.4, methionine + cysteine 4.0 (in a diet containing 0.6 cysteine), phenylalanine + tyrosine 5.6 (in a diet containing 1.9 tyrosine), tryptophan 1.0 and valine 4.6. Moreover, the optimum dietary n-3 long chain polyunsaturated fatty acids and soybean lecithin are recommended to be 0.8% and 6%, respectively. The maximum replacement of fish meal with soy protein is recommended to be between 16.5% and 27.3%. In addition, different vegetal oil sources are also recommended for partial and almost complete replacement of fish oil in diets. Although the nutritional requirements in terms of macronutrients have been established under laboratory conditions, the analysis of the available literature indicate that future studies need to be conducted using a more holistic approach under intensive farming conditions in which different nutrients or additives need to be tested under different rearing conditions for refining nutrient requirements in this species.info:eu-repo/semantics/publishedVersio