- Email: [email protected]
Rotifer Symposium V
292
BOOK REVIEWS
the economically important species were divided into two groups, fishes with or without a stomach, instead of the generally accepted subdivision of fish into predatory and non-predatory species. Macro-nutrients such as proteins, fats and carbohydrates are subjects of the third section. Protein, amino acid and fatty acid requirements and availability or digestibility of these nutrients are described, emphasizing the differences among fish species. Reflecting the increasing importance of dietary energy content, “Energy requirement” is independently discussed in the fourth section. Significant contributions by German scientists on efficient utilization of dietary energy and optimal protein/energy ratios are well documented, including those written in German which tend to be neglected by readers who cannot read German. Micro-nutrients such as vitamins and minerals are dealt with separately in sections live and six. The latest developments in the studies on trace elements are well covered in this section. The author also presents large numbers of original descriptive figures ( 10 1) and tables ( 162) which are very useful but, in certain cases, there is some confusion where the data have not been well digested by the author. For instance, the author concludes that the great importance of the pyloric caeca for digestion and resorption is clearly apparent from the fact that their serosal surface is much larger than that of the intestine ( p. 44, bottom line), whereas, on the next page, he cites a reference which states that no relationship could be established between the number and length of pyloric caeca and digestibility for either fat or protein. The bibliography of more than 1400 references and the subject and author indexes enhance the potential usefulness of this book for students and academic and industrial researchers. Except for a few words that have been translated to a form not commonly used by fish nutritionists, such as “fishery culture”, “ proteids” and “isodynamics”, the translation is fairly well done. T. MURAI Research Coordinator, National Research Institute of Fisheries Science, Tokyo 104, Japan
ROTIFER SYMPOSIUM
Rotifer Symposium
V. C. Ricci, T.W. Snell and C.E. Ring (Editors). Kluwer Academic Publishers, Dordrecht, 1990. Reprinted from Hydrobiologiu ~01s. 186/ 187 ( 1989). 464 pp., price Dfl. 350.00/&l 16.00, ISBN o-7923-041 3-6.
Out of 53 contributions to this symposium there are several papers of interest to the readers of Aquaculture. First of all the last part (live) deserves
BOOK REVIEWS
293
the attention of those involved in or interested in developing cultivation of rotifers and feeding them to fish. The paper by Lubzens, Tandler and Minkoff, “Rotifers as food in aquaculture” reviews the state of knowledge on this animal as food for larval stages of, mostly, marine fish species. The authors discuss the role of rotifer size and their electivity by fish larvae, some ways of obtaining required sizes, and the distribution and concentration of these animals in larval tanks, pointing to the significance of light and nutritional aspects. Of interest is, inter alia, the significance of the highly unsaturated fatty acids. Their content in rotifers can be regulated to some extent by what kind of food is offered, and it was found that baker’s yeast is not adequate. Enrichment of rotifer diets with substances rich in these acids was tested. There is a paper related to this problem: “Kinetics of n-3 fatty acids in Brachionus plicatilis and changes in the food supply” by Olsen, Rainuzzo, Vadstein and Jensen. They found that rotifers fed with micronized herring roe powder became rich in these acids. Three other papers in this part of the proceedings consider certain aspects of rotifer (Brachionus plicatilis) culture: nitrogen flow in rotifer-on-Chlorella mass culture; egg incubation and preservation; and the use of chemostats in intensive rotifer culture. It should be noted that all these papers deal with Brachionus. In other parts of the proceedings there are at least three contributions which may be of interest to aquaculture: nutritional effects of freshwater Chlorella on the growth of Brachionus (by Hirayama, Maruyama and Maeda); the same rotifer fed different algae (by Komstad, Olsen and Vadstein); and the tolerance of this species to low oxygen concentrations (by Esparcia, Miracle and Serra). For those who would like to start or to improve the use of rotifers (in fact one species of Brachionus is dealt with) as food for fish larvae, these papers are certainly interesting, but to start cultivation of these animals one should study technical details which are to be found elsewhere. In particular, references included in the paper by Lubzens. Tandler and Minkoff could help in this matter. The general impression of a “non-rotiferologist” is that the book offers a very interesting bulk of knowledge on systematics (with beautiful electronmicroscope photos in one of the papers), on ecology, physiology and genetics of this group of animals, and one may wonder why aquaculture utilizes practically one species only. In think that suggestions from rotifer experts with respect to the possible candidates for culture would be highly appreciated. T. BACKIEL
Inland Fisheries Institute Olsztyn. Ponds & River Fish. Depts, Zabieniec near Warsaw, 05-500 Piaseczno, Poland
BOOK REVIEWS
the economically important species were divided into two groups, fishes with or without a stomach, instead of the generally accepted subdivision of fish into predatory and non-predatory species. Macro-nutrients such as proteins, fats and carbohydrates are subjects of the third section. Protein, amino acid and fatty acid requirements and availability or digestibility of these nutrients are described, emphasizing the differences among fish species. Reflecting the increasing importance of dietary energy content, “Energy requirement” is independently discussed in the fourth section. Significant contributions by German scientists on efficient utilization of dietary energy and optimal protein/energy ratios are well documented, including those written in German which tend to be neglected by readers who cannot read German. Micro-nutrients such as vitamins and minerals are dealt with separately in sections live and six. The latest developments in the studies on trace elements are well covered in this section. The author also presents large numbers of original descriptive figures ( 10 1) and tables ( 162) which are very useful but, in certain cases, there is some confusion where the data have not been well digested by the author. For instance, the author concludes that the great importance of the pyloric caeca for digestion and resorption is clearly apparent from the fact that their serosal surface is much larger than that of the intestine ( p. 44, bottom line), whereas, on the next page, he cites a reference which states that no relationship could be established between the number and length of pyloric caeca and digestibility for either fat or protein. The bibliography of more than 1400 references and the subject and author indexes enhance the potential usefulness of this book for students and academic and industrial researchers. Except for a few words that have been translated to a form not commonly used by fish nutritionists, such as “fishery culture”, “ proteids” and “isodynamics”, the translation is fairly well done. T. MURAI Research Coordinator, National Research Institute of Fisheries Science, Tokyo 104, Japan
ROTIFER SYMPOSIUM
Rotifer Symposium
V. C. Ricci, T.W. Snell and C.E. Ring (Editors). Kluwer Academic Publishers, Dordrecht, 1990. Reprinted from Hydrobiologiu ~01s. 186/ 187 ( 1989). 464 pp., price Dfl. 350.00/&l 16.00, ISBN o-7923-041 3-6.
Out of 53 contributions to this symposium there are several papers of interest to the readers of Aquaculture. First of all the last part (live) deserves
BOOK REVIEWS
293
the attention of those involved in or interested in developing cultivation of rotifers and feeding them to fish. The paper by Lubzens, Tandler and Minkoff, “Rotifers as food in aquaculture” reviews the state of knowledge on this animal as food for larval stages of, mostly, marine fish species. The authors discuss the role of rotifer size and their electivity by fish larvae, some ways of obtaining required sizes, and the distribution and concentration of these animals in larval tanks, pointing to the significance of light and nutritional aspects. Of interest is, inter alia, the significance of the highly unsaturated fatty acids. Their content in rotifers can be regulated to some extent by what kind of food is offered, and it was found that baker’s yeast is not adequate. Enrichment of rotifer diets with substances rich in these acids was tested. There is a paper related to this problem: “Kinetics of n-3 fatty acids in Brachionus plicatilis and changes in the food supply” by Olsen, Rainuzzo, Vadstein and Jensen. They found that rotifers fed with micronized herring roe powder became rich in these acids. Three other papers in this part of the proceedings consider certain aspects of rotifer (Brachionus plicatilis) culture: nitrogen flow in rotifer-on-Chlorella mass culture; egg incubation and preservation; and the use of chemostats in intensive rotifer culture. It should be noted that all these papers deal with Brachionus. In other parts of the proceedings there are at least three contributions which may be of interest to aquaculture: nutritional effects of freshwater Chlorella on the growth of Brachionus (by Hirayama, Maruyama and Maeda); the same rotifer fed different algae (by Komstad, Olsen and Vadstein); and the tolerance of this species to low oxygen concentrations (by Esparcia, Miracle and Serra). For those who would like to start or to improve the use of rotifers (in fact one species of Brachionus is dealt with) as food for fish larvae, these papers are certainly interesting, but to start cultivation of these animals one should study technical details which are to be found elsewhere. In particular, references included in the paper by Lubzens. Tandler and Minkoff could help in this matter. The general impression of a “non-rotiferologist” is that the book offers a very interesting bulk of knowledge on systematics (with beautiful electronmicroscope photos in one of the papers), on ecology, physiology and genetics of this group of animals, and one may wonder why aquaculture utilizes practically one species only. In think that suggestions from rotifer experts with respect to the possible candidates for culture would be highly appreciated. T. BACKIEL
Inland Fisheries Institute Olsztyn. Ponds & River Fish. Depts, Zabieniec near Warsaw, 05-500 Piaseczno, Poland