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Použití obohacených nauplií artemie pro odkrm larev ryb
BARTOŠ, Ondřej
The aim of study was to create review about breeding and use of enriched Artemia salina. Firstly, the historical development of use of Artemia salina was described, as well as its demands on biotop and its morphology. Secondly, the feeding larval stages of fish with different developmental stages of Artemia salina was concerned. Especiallymthe description of bioencapsulation of Artemia salina as well as the description of several commercial bioencapsulational agents were included (Selco, AlgaMac-3050). Some experiments focused on the growth and survival of some fish species which were feeded with Artemia salina were concerned in this study. These fish species were involved: Oncorhynchus mykiss, Sander lucioperca, Acipenser persicus, Huso huso, Tor khudree, Acanthopagrus latus Cromileptes altivelis a Hippocampus abdominalis. The majority of bioencapsulational agents involved in the experiments were supposed to result in increase in the concentration of highly unsaturated fatty acids (HUFA) and in increase in the content of vitamines. The size of Huso huso that was feeded with enriched Artemia salina was a half higher (4,2g ? 0,5g) in comparison with the size of fish species feeded with unmodified Artemia salina (2,8g ? 0,2g). The similar results occured in the case of Oncorhynchus mykiss. The observed group of Oncorhynchus mykiss which was enriched with the mixture 10 % HUFA and vitamin C was of the weight 657,5mg ? 57,9mg and the survival ratio 96 % ? 1 %. The control gained the weight 568,3mg ? 20,7mg and survival ratio 67 % ? 1 %. As a result of this study it is obvious that feeding larval phases of fish with the enriched Artemia salina has a positive effect on their growth and survival.
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Odkrm plůdku lína obecného (Tinca tinca) s využitím obohacených nauplií žábronožek (r. Artemia)
BOŇKO, Dominik
The aim of the experiment was investigate the the effect of feeding early Tench fry with enriched Artemia nauplii on the survival in the under laboratory conditions at an average water temperature of 25.8 °C. The total duration of the experiment was 42 days. We used two commercial enriching products of Selco company (Selco DHA and Selco Spresso). The fry were fed with this diet in two variants (7 and 21 days), followed by a transition to dry starter feed. In the experiment were also included control groups fed with unenriched nauplia (also for 7 and 21 days). The transition to starter feed (Inicio Plus GR from Biomar) was done after a four-day co-feeding, when the proportion of nauplia was gradually reduced. Groups fed with naplii for 7 days had a higher growth rate (13.41 %-d-1), an average individual weight (142.74 +- 57.06 mg) and a total length (21.08 +- 3.27 mm), including higher variability of the two last parameters. At the same time, low survival (2.8 %) was observed. Produced biomass was also lower. Fry fed with live feed for the first 21 days had lower growth rate (10.77 %-d-1), individual weights (48.61 +- 18.13 mg) and total length (16.05 +- 1.66 mm). Survival of fry was much higher (25.1 %) in this case. Produced biomass of the fry fed with live food for three weeks was almost three times higher (219.3 g) than biomass of the fry fed with live feed for one week (71.4 g). It can be observed that the influence of enriching of the artemia nauplii on the growth of the tench fry wasn´t proved. However, fry fed a week of enriched nauplii reached a slightly higher survival rate during the rearing period. Compared with the control group (3.3 %), the survival rate of the fry fed with live food enriched of Selco Spresso was 3.7 % . The survival of Selco DHA was 1.4%. Reached results could be partially influenced by parasitic disease of the fry during rearing.
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Length and weight growth of early pikeperch fry fed with enriched artemia nauplii in experimental conditions
JANKOVÝCH, Antonín
The aim of our experiment was proving the suitability and effectivity of artemia nauplii enrichment in pikeperch fry rearing. 24 hour enrichment took place in 3 variants: 1. SELCO, 2. 18 (n-3) (alfa-linolenic acid) and 3. 18 (n-3) + vitamin C. Original intention was initializing fry feeding with different types of enriched artemia metanauplii. Due to excessive size of artemia after 1 day enrichment (Artemia franciscana) (in comparison with size of fry oral cavity) the intake of such food was not possible, thus the metodics had to be modified. From the given reason, fish were initially fed with unenriched nauplii ; firstly with dose 100 ml (4 - 8 day post hatch - dph) after that with dose 50 ml per tank (9. dph 25.4.). As soon as fry reached suitable size and was able to intake bigger size of nauplii, was in the second part feeding diferenciated (use of different types of enrichment and control group was fed with unenriched artemia). First part of experiment lasted 22 days (5.4. - 26.4.), fish must have been netted and again placed in tanks for experiment with enriched artemia. Second part of rearing varied in use of differently enriched metanauplii and lasted 8 days (27.4. - 4.5.). At the end of second part of feeding (from 1.5.) was involved co-feeding, which means combined feeding (living food and starter feed). 5.5. was experiment terminated. The highest survival was reached in group fed with artemia enriched in comercial preparate SELCO (28,67 %), second highest survival was reached in group fed metanauplii enriched in alfa-linolenic acid (27,88 %) and third highest survival was reached in group fed with alfa-linolenic acid and vitamin C enriched metanauplii (19,00 %). The highest individual fry weight at the end of experiment was reached in group fed with artemia enriched in alfa-linolenic acid and vitamin C : 306,16 +- 64,27 mg, the lowest individual weight was reached in control group : 216,9 +- 39,96 mg. The highest average total lenght (l.t.) was measured in SELCO group 30,13 +- 2,47 mm, the lowest total lenght reached fish in control group 27,37 +- 1,32 mm. In group fed with artemia enriched in vitamin C was noticed the highest percentage of starter feed intake (8 %), but simultaneously in the same group was reached the highest rate of cannibalism (6 %).
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