Thet, Thet Nwe creator Little, David C. Chairperson Upasena, Selawa H. Co-Chairperson Suthad Setboonsarng Examination Committee Japan Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 1992 continuing eng 76 leaves The general a:i m of the study was the development of the feeding system of duck rearing by using protein-rich duckweed as substitutes for concentrate feed. The study involved raising of ducks receiving different levels of duckweed. More specifically , attention was also paid to invest:i.ga t e the growth of performance and survival of ducks based on the duckweed substitution. The subsidiary aim was to investigate the gowth performance and survival of muscovy male and khaki campbell male ducks which were usually reared for the purpose of meat consumption within the s mall- scale farmers' level . The experiment can be described as t wo parts. Th e first included mal e starter ducks which were raised intensively in cages for 3 weeks fed different levels of concentrate diet a nd duckweed ad libitum. Growth of ducks, mortality and faecal composition were recorded and compared between treatment levels and species in order to know the effect of duckweed substitution on starter stage of ducks. The second part of the experiment was run for 8 weeks grower period. In this part, the male grower duck were raised semi-intensively, allowed to scavenge free range during the day time and fed village rice bran ad libitum as supplementary in the evening after coming back to the shed from scavenging area. Body weight, mortality and feed consumption were recorded, and compared not only between treatment levels but also between species in order to know how do the duckweed substitution of starter stage affect on the grower stage of ducks. An increase in the level of concentrate feed :is accompanied by an increase in the growth of ducks in both muscovy and khaki campbell. At the end of the experiment, survival of muscovy ducks was unaffected until the level of concentrate feeding was reduced to 40% of the ad 1ibitum level . At lower concentrate feeding levels, survival of khaki campbell hybrid was particularly affected . Complete mortality occurred :in both ducks when concentrate feed was less than 20% of ad libitum levels. Muscovy respond to duckweed substitution w:ith a higher rate in growth, survival, carcass yields, feed conversion and disposal of waste. The composition of feedstuffs given to the ducks affect on the quality of manure. An increase in the level of concentrate feed is accompanied by a n increase in the level of dry matter, total nitrogen and total phosphorus. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1992 Lemnaceae Ducks Feeding and feeds Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B16591 http://203.159.5.9/ait-thesis/detail.php?q=B16591 111010 20260818094225.0