The Nutritional Value of Live Foods on the Larval Growth and Survival of Japanese Flounder,Paralichthys olivaceus

Abstract

The Japanese flounder, Paralichthys olivaceus, is one of the most common finfish cultured in Japan and Korea. Despite the relatively high production of fingerlings, some problems remain, mainly related to the larval feeding and cost of maintaining microalgae and rotifers. In order to determine the effects of different diets on the Japanese flounder larval growth and survival, a series of experiments was carried out related to the size and nutritional value of different live feeds. The larvae culture conditions were at 10 or 20 larvae/L in 50 to 2,000 L tanks, with aeration and with or without "green water," and a temperature range of 18.5 to 22.5°C. The live foods used were microalgae (Chlorella ellipsoidea and Nannochloris oculata), baker's yeast, experimental n-yeasts, oyster trochophore larvae, three strains of rotifer Brachionus plicatilis (L-type, S-type and U-type) and Artemia nauplii. Variations were detected in size, dry weight, and chemical composition of the three strains of rotifers used. The maximum number of rotifers ingested by flounder larvae increased steadily from 7 individuals, at first feeding (3.13 mm), to 42 individuals at 5.25 mm of total length (6 days after first feeding). There was a relationship between larval total length and size of the rotifers ingested. The effect of rotifer size on larval growth and survival appeared to be limited to the first two days of feeding. Of the diets tested in the growth and survival of larval flounder during 14 days after hatching, rotifers fed on C. ellipsoidea and raised in green-water gave the best results. Rotifers cultured on enriched N. oculata and n-yeasts did not support larval growth and caused higher Downloaded by [University of Otago] at 03:00 26 December 2014mortalities. The n-yeasts used as rotifer enrichment appeared to satisfy, partially, the nutritional requirement of 7-day-old flounder larvae, as did n-yeast squid wintering oil the requirements of 14-day-old larvae. From 7-9-days after hatching and throughout the second 14-day period, rotifers and Artemia cultured on N. oculata improved the survival of flounder compared with those fed on rotifers cultured on C. ellipsoidea. Moreover, the larval growth did not vary significantly between both microalgae-rotifer feedings. No clear relation was found between total protein, lipid, amino acids and fatty acids of live feeds with the growth and survival of flounder larvae, although the total lipid was higher in C. ellipsoidea than in N. oculata. The Artemia nauplii San Francisco strain appeared to be more suitable for the growth and survival of flounder larvae, than the Utah strain. The nutritional value of Artemia nauplii (Utah strain) for flounder larvae remained unchanged despite the use of either microalgae as nauplii enrichment.

Oyster larvae as a potential first feed for small-mouthed ornamental larval fish

“…Although P. hepatus readily consumed oyster larvae, the growth and survival of P. hepatus fed oyster trocho phores that subsequently developed into veligers was similar to unfed controls. This is similar to Lim (1993) and Cabrera & Hur (2001), who ob served poor growth and survival of fish larvae fed exclusively bivalve trochophores and veligers. Con versely, Howell (1979) found high survival (80%) in Scophthalmus maximus larvae fed oyster veligers, although larval length and survival was greatest when their diet contained rotifers.…”

“…(B) 3 dph P. hepatus larvae fed oyster trochophores exposed to pH 4.8 seawater. Digestion of trochophores is evidenced by lack of visible intact oysters and homogenous grey matter in the gut previously tested as a live feed for fish larvae (Howell 1979, Lim 1993, Cabrera & Hur 2001, this study is the first to use acidic water to compromise oyster trochophore calcification to improve its value as a live feed. Acidic conditions impact the ability of bivalve larvae to calcify and cause abnormalities (Parker et al 2009, Gazeau et al 2013.…”

“…Larval P. hepatus readily consumed oyster trochophores and veligers. The larvae of a wide range of fish species consume bivalve larvae when offered as a live feed during larviculture (Howell 1979, Harding 1999, Cabrera & Hur 2001, Ma et al 2013, Harding et al 2015. Bivalve larvae are rarely found in the guts of wild oceanic fish larvae, probably because bivalves are rare in these environments (Llopiz 2013, Djurhuus et al 2018.…”

“…Oysters provision their larvae with high levels of the nutrients that are required by larval fish, including protein and polyunsaturated fatty acids (PUFAs) as both neutral lipids and phospholipids (Chu & Webb 1984, Massapina et al 1999, Soudant et al 1999, Caers et al 2002. Oyster and other bivalve veligers are consumed by fish larvae in the wild and in captivity (Howell 1979, Harding 1999, Cabrera & Hur 2001, Harding et al 2015, Nack et al 2015, although survival rates of fish larvae fed oysters vary considerably among species (0−80%) (Howell 1979, Watanabe et al 1996, Cabrera & Hur 2001. Further research is required to fill knowledge gaps about the potential of oyster larvae as live feeds for many types of fish, such as the larvae of marine ornamental finfish (Oliver et al 2017).…”

Development of Economical Fertilizer-Based Media for Mass Culturing of Nannochloropsis oceanica

“…Using agricultural fertilizers only, however, leads to the problem of lower cell growth rates than in common media such as f/2 (Guillard and Ryther, 1962). Nannochloropsis oceanica is commonly used to culture rotifers for marine fishes (Cabrera et al, 2005;Kobayashi et al, 2005;Ferreira et al, 2009) and to create "green water" for nursery tanks (Cabrera and Hur, 2001) because they are nutritious and easy to mass-produce. Additionally, their high contents of vitamins (Brown et al, 1997), lipids (Patil et al, 2007;Seychelles et al, 2009), highly unsaturated fatty acids (Sukenik et al, 1993;Zittelli et al, 1999;Hu and Gao, 2003), protein (Volkman et al, 1993), and natural pigment (Lubián et al, 2000) distinguish N. oceanica as a prospective microalgal species to be further researched and developed for the marine…”