block 1 chapter 1.pdf

Block 1 : C1: Concepts & def. of growth Status Done Assign W Due @March 20, 2023 Project Week 1 Documents 2023 Aquac-block1-c1.pdf Lecture Wanda WUR Schama Refferences Reviewed? factor affecting fish growth and performance why is growth important in aquaculture? because the ultimate go...

Block 1 : C1: Concepts & def. of growth Status Done Assign W Due @March 20, 2023 Project Week 1 Documents 2023 Aquac-block1-c1.pdf Lecture Wanda WUR Schama Refferences Reviewed? factor affecting fish growth and performance why is growth important in aquaculture? because the ultimate goal in aquaculture is the production of operation, which is for business and profit. and to achieve particular growth, it`s implies by boost the growth and weight. which factors affecting growth? in general, factor that affecting growth are: feed conversation ration, the amount if feed that converted into 1 kg of meat fish. which later determine the feed cost. growth rate, this influence the time needed for reach a certain weight survival, this will influence the seed cost of fish quality of the end product, this will influence the price obtained Block 1 : C1: Concepts & def. of growth 1 how is the classification factors variation in growth? fish as the internal condition species sex health history of the fish such as age, weight, body composition genetics, such as breeding, domestification environment as the external candition husbandary, such as density, handling, feeding method water quality, such as temperature, oxygen, metabolites feed the level composition formulation, like the ingredient type, like the physical aspects growth description what is growth? growth is define as increase in size of fish overtime. the size increase can be quantified as volume, mass, length, energy, protein fat, or dry matter. Block 1 : C1: Concepts & def. of growth 2 the curve of growth how is factor affecting growth? Block 1 : C1: Concepts & def. of growth 3 under normal condition under sub-optimal condition under sub-optimal condition what causes the high growth rate during a period of compensatory growth? compensatory growth is the accelerate growth. the fish which live in a habitat where feed is available whole year, ofetn hardly show a low or no capacity for compensatory growth Block 1 : C1: Concepts & def. of growth 4 higher feed intake or hyperphagia, the extreme unsatisfied drive to consume food higher efficiency due to the increase digestibility or reduce maintenance requirements higher digestibility lower maintenance change in body composition the compensatory growth how is the variability of environment including nutrition and growth? in a certain of time, some part of fish body is taken for body basis, length, reverse, and egg production. during spawning, the fish growth in energy will be higher, because some of their energy used for egg production. Block 1 : C1: Concepts & def. of growth 5 the seasonal variation in fish growth how is the curve for total amount of body energy over time? in the crustacean, they periodically loosen the connectives between their epidermis and extracellular cuticle. they rapidly escape from old exoskeleton followed by the uptake water to expand the new one. the flexible exoskeleton quickly hardening with protein and minerals. the molting process is responsible in the discontinue nature of growth in crustacean. by molts and water is replaces by tissue (protein and fat). at molting, the dry matter content of crustacean decrease and between molts, the dry matter content increases Block 1 : C1: Concepts & def. of growth 6 discontinue nature of growth in crustacean how is the relation feed intake and growth? when fish starved they lose their body because they mobilise body reverse, such as energy, protein, and fat to maintain the vital process. the feed ration is dependent nutrition factors, (composition, and pellet quality), animal related (sex and genotype), environmental related factor (water content, oxygen, carbon dioxide, DO, NH4) when the ration increase, the the growth will be increase from negative value (G.star) at feed deprivation (the condition of not having something) toward maximum (G.max). (R.opt)the optimal ration, is a condition where the feed ration at which the conversion efficiency is maximal (R.m) the maintain ration, is a condition where the feed ration at which growth is zero. the definition of R.m differ growth expressed on weight basis and growth Block 1 : C1: Concepts & def. of growth 7 expressed on energy basis. that`s caused by the fish that higher priority for protein gain than fat gain at low feeding ration. since protein is always coincide with water gain in contrast to fat gain, a positive weight gain occurs when energy per gram is higher for fat than protein. thus a positive weight gain occurs when energy gain is zero. consequently, the fish (R.m) become leaner the relation of feed intake and growth Block 1 : C1: Concepts & def. of growth 8 the relation of feed intake and growth in carp what is the possible reason of declining in growth rate with increasing feeding ration? 1. the fish which receive higher ration have grown bigger, and there fore lwer specific growth rate 2. increase feeding ration may also coincide with increase the amount of feed waste . consequently, at higher feeding ration, some fish may have reach maximum feed intake 3. with increasing feed ratio, the composition of growth can change. if the ration between fat and protein gain change with feeding ration, this ration will be increase with feeding ration. when expressing growth on fresh weight bases, higher percentage of fat gain will result reduction in the feed conversion efficiency Block 1 : C1: Concepts & def. of growth 9 the relation of feed intake and growth what are factors causing a curvilinear relationship between growth and feed ration? 1. experimental error 2. more feed spillage 3. change in body composition 4. growth measured in groups, individual variation in R.max what are factors causing curvilinear relationship between growth and feed ration? factors which required for growth but are not harmful. when this factors increased, the growth will also increase until the inflection point. after the inflection point, the growth is unaffected by this factors. eg. nutrient, and oxygen Block 1 : C1: Concepts & def. of growth 10 factors which required for growth factor which can be harmful or stressor for fish when exceeding the value. at low value, that factor is not affect growth, but when the value is exceeding. the growth will be negatively affected. eg. Nh4, Co2, toxins factors which can be harmful when exceeding the value factors which characterised by exhibiting an optimal value regarding its impact on growth performance. those factors are combination of two factors mentioned before. with increasing values of such factors, growth will be increase Block 1 : C1: Concepts & def. of growth 11 then reach a maximum. this maximum can be a point but also a range of value where growth is not affected by the factor. eg. temperature, ph, stocking density factors which characterised by exhibiting an optimal value how the relationship between feed ration and growth can be affected by other factors than feeding level? eg. the situation that can be influence the oxygen content. as we know, the oxygen content can positively affect the maximal feed intake in fish. when the oxygen concentration decreased, the maximal feed intake will declined. consequently, when increasing feeding ration, the fish will reach its maximal feeding ration (R.m) earlier, and the maximum growth rate (G.max) will be lower. this condition is similar with genetic selection for growth. Block 1 : C1: Concepts & def. of growth 12 by affecting max growth rate in area where the factor feeding ration does not determine growth rate eg. feed quality (dietary protein content) that can be influence the feeding ratio. at low dietary quality, the sloop of the relation between feeding ration and growth will be smaller. in other words, the efficiency with one gram of extra food is used for growth of lower when the diet quality is low. Block 1 : C1: Concepts & def. of growth 13 by affecting the sloop of linear line between growth rate and feeding ration in the area of the curve where growth is dependent upon the feeding ration eg. swimming activity, a high swimming activity will have higher maintenance requirements and consequently have a lower growth rate at similar feeding ratio compared with fish with low swimming activity. by shifting the complete curve to the left or right along the x axis without changing its shape Block 1 : C1: Concepts & def. of growth 14