Thesis (Ph. D.)--University of Nebraska, 1913. / "Studies from the Zoölogical laboratory University of Nebraska, no. 109." "Reprinted from the Journal of experimental zoölogy, vol. 15, no. 2, August 1913." Bibliography: p. 254-255.

No description available.

Thesis (PH. D)--Columbia University. / Cover title. Academic record. Reprinted from the Journal of experimental zoology, 1907, vol. V., no. 1; 1909, vol. VI, no. 1. Bibliography: p. 26, 135-136, 145-146.

Inaug.-diss.--Basel. / Vita. "Literaturverzeichnis": p. [170]-175.

Inaug.-diss.--Basel. / Vita. "Literaturverzeichnis": p. [170]-175.

No description available.

No description available.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 39-44). Also available on the World Wide Web.

Rotifers of the species Mytilina brevispina var redunca were cultured at 24°C under standard and aseptic culture conditions in artificial saline media of three calcium concentrations. 1. All populations were homologated with respect to maternal age by a process of egg selection carried out over three generations. 2. Observations on survival, growth and egg production were made on populations cultured on the three media containing a-full and reduced diet, while the effects of transfer between culture media, periodic washing in chelating agents, and constant exposure to antioxidants were tested on survival and egg-laying in Control cultures. 3, The calcium content of rotifers was investigated by continual exposure to the radionuclide 45 calcium in the three culture media, while the 45 calcium accumulated and withdrawn from rotifers cultured on Control 45 calcium medium and subjected to treatment with the chelating agent sodium citrate, and the 45 calcium accumulated in rotifers cultured on Control 45 calcium medium containing the antioxidant B.H.T., were also investigated. The 45 calcium intake of algae cultured for one day on Control 4-5 calcium medium at the concentration normally employed for experiments was noted. 4. In the case of rotifers cultured on a full diet in the three calcium media the greatest longevity, egg' total, and reproductive period was recorded in the Low calcium cultured population, while the lowest longevity value and total number of eggs laid was recorded in the High calcium group. Continual exposure to 4-5 calcium in each of the three media, revealed an accumulation of calcium that began in all cases at the end of the period of growth in size. This accumulation occurred at a rate that was inverse.ly related to longevity and directly related to the level of radionuclide in each medium in the manner predicted by the Lansing hypothesis. The total 45 calcium taken up in the daily intake of algae in 4 day old rotifers cultured on Control medium approximately the same order as the maximum rate of 45 calcium accumulation in untreated rotifers cultured on the same medium, suggesting a possible source of calcium accumulation in the event of a breakdown in the mechanism of excretion. 5. Rotifers cultured on a reduced diet in each of the three media showed an increase in longevity, egg total and reproductive period compared with rotifers cultured in the corresponding media on a full diet. However, the relative differences with respect to these characteristics were approximately similar between populations cultured on the same dietary level, with the Low calcium cultured population showing the greatest increase in longevity, total egg production and reproductive period. No execution in the growth period or difference in final size was noted in the case of the dietary restricted groups (cf McCay's starvation studies). 6. The results of the culture transfer experiments in which rotifers were transferred to another of the three media at the end of the growth period, revealed that it was the medium on which rotifers were cultured after growth that exerted the major influence on longevity value, total egg production and length of reproductive period. This result is in agreement with the appearance of an ageing factor at the end of the period of growth size postulated in the Lansing ageing theory.

Nutritional aspects of three species of marine fish larvae, herring Clupea harengus L., plaice Pleuronectes platessa L. and turbot, Scophthalmus maximus L. were examined. Larvae were fed three different diets all of which were derived from rotifers Brachionus plicatilis (O.F. Mtlller). These rotifers had been mass cultivated on baker's yeast and then enriched with baker's yeast, or with one of two unicellular algae, Isochrysis galbana Park or Nannochloropsis (Nannochloris) oculata (Droop) Hibberd. The biochemical changes that these enrichments conferred on the rotifer were examined. There was little difference in proximate and amino acid compositions. Dry weights, and calorific contents of the rotifers fluctuated according to the type, temperature and duration of enrichment, with the yeast enriched rotifers tending to weigh less (200-320 ng) than their algal counterparts (250-370ng). Major differences were found in the total fatty acid profiles of the rotifers. Yeast-enriched rotifers had no 18:3n-3 or 20:5n-3 and only trace amounts of 22:6n-3 fatty acids. The Nanrinochioropsis-enriched rotifers had substantial amounts of n-3 fatty acids though only of 20:5n-3 (11-14%), while rotifers enriched with Isochrysis had only trace amounts of 20:5n-3 (2-4%). All three species of fish responded similarly to the yeast enriched rotifer diet. Their growth, in terms of length and weight, was minimal and they never developed any fin ray elements. Both flatfishes developed a looped gut in the short growth duration on this diet and some turbot (20%) inflated their swim bladder. This retardation of growth was attributed to the lack of long chain highly unsaturated n-3 fatty acids (n-3 HUFA) in the diet. During one month feeding trials it was shown that herring and plaice were able to exploit both algal-enriched rotifer diets equally well. Turbot, on the other hand grew better, over 14 days, on rotifers enriched with lsochrysis compared with Nannochioropsis. The reaction of the different species was linked to the fatty acid profiles of the diet. Hence, turbot require a dietary input of 22:6n-3 while herring and plaice thrived equally well on diets containing only 20:n-3. Juvenile plaice consistently exhibited improved pigmentation when Isochrysis compared to Nannochloropsis were used as the rotifer enrichment. The effect was attributed to specific nutrients particular to algal chloroplasts, which need to be present in the diet of the larvae up to metamorphosis. Assessment of daily rations, employing the rotifer enriched with Isochrysis diet only, showed herring to reduce their food intake from 46 to 19% body dry weight/d between days 10-21 post hatch while turbot consumed between 34-169% body dry weight/d with no apparent age related effects. The gross growth efficiencies (Ki, Brett & Groves, 1979) for both species were seemingly unaffected by age related processes and fluctuated between 15-50% in turbot and 20-61% in herring according to fluctuations in daily food intake. Ingestion is further described for both species with a linear model that related food intake to larval weight. The weight-specific ingestion was found to be a constant 13% and 43% of body dry weight in herring and turbot respectively. The weight-specific ingestion and specific growth rate estimates were combined with other data available from the literature, revealing that larvae tend to consume food (in dry weight) at a level equivalent to approximately twice their daily dry weight increase.