Lower Feed Costs Research Articles

Forty-Eight-Hour Cycle Sequential Feeding with Diets Varying in Protein and Energy Contents: Adaptation in Broilers at Different Ages

Sequential feeding is a cyclic feeding program with 2 diets for 1 or several days used to induce lower feed costs or to improve welfare quality. The aim of the present study was to investigate the effects of energy [2,800 (E-) and 3,200 kcal/kg (E+)] and protein [230 (P+) and 150 g/kg (P-)] content on daily feed intake and growth in 900 male broiler chickens, and to compare these results with standard feeding (CP = 190 g/kg and ME = 3,000 kcal/kg). Sequential feeding was carried out during 48-h cycles in 2 periods (period 1 = 10 to 17 d of age, period 2 = 18 to 29 d of age). Four treatments were compared during periods 1 and 2: 1) complete diet (C), 2) alternation of diets varying in CP (SP = P+ followed by P-), 3) in energy (S(E) = E- followed by E+), 4) in protein and energy contents (S(EPA) = P+E- followed by P-E+). A fifth treatment (S(EPB)) used an alternation in protein and energy contents during period 2 only. All chickens received the same feed during the finishing period (30 to 35 d of age). Feed intake was similar with sequential feeding and complete feed, but in proportion to total feed intake, chickens overconsumed high energy feeds (E+ and E+P-) during each period, and P- only for period 2 (P < 0.01). During period 2, overconsumption was greater with S(EPA) than S(EPB) (P < 0.01). Weight gain was similar for all treatments during period 1. At 35 d of age, S(E) chickens were heavier than S(EPA) and S(EPB) (P < 0.01). Feed to gain ratio was similar for all treatments for period 1 and increased for S(P), S(EPA), and S(EPB) compared with C and S(E) for period 2 (P < 0.01). Walking ability, carcass conformation, breast yield, and abdominal fat did not differ between treatments, but ultimate pH of breast meat was improved with S(P). In conclusion, growth and slaughtering performances similar to standard feeding can be reached with 48-h cycle sequential feeding using diets varying in protein and energy contents.

Response to Varying Dietary Energy and Protein With or Without Enzyme Supplementation on Growth and Performance of Leghorns: Growing Period

Bovans White Leghorn pullets were utilized to evaluate the use of an enzyme cocktail from 0 to 126 d of age. Dietary treatments varied in CP, ME, and enzyme (EZ) supplementation. Feed intake, BW gain, and feed conversion ratio data were gathered in addition to determining nutrient retention and digestibility during the trial. Cumulatively, feed consumption was decreased by EZ supplementation when added to a required ME diet. Body weight gains were similar across dietary treatments; however, cumulative feed conversion ratio was significantly improved with EZ supplementation. Interactions regarding nutrient retention and digestibility were numerous. Similar responses were noted for energy and protein retention values during the trial with changes in response to dietary treatments as the pullets aged. Compared with feeding an industry applicable diet (required ME/CP without EZ − $0.27/lb gain), all dietary treatments reduced production costs with significant reductions when reducing CP. Lowest feed cost ($)/lb gain and percent excreta N was feeding pullets a diet with reduced ME and CP supplemented with EZ ($0.262/lb gain; 5.19% N). Possible further reductions in ME or dietary CP, or both, with EZ supplementation may prove to be even more economical and environmentally friendly.

Apparent digestibility coefficient of protein and amino acids of acid, biological and enzymatic silage for Nile tilapia (Oreochromis niloticus)

Using the fish silage to partially replace proteic feedstuff in aquafeeds is an alternative to mitigate sanitary and environmental problems caused by the lack of adequate destination for fisheries residues. It would also lower feed costs, consequently improving fish culture profitability. However, using fish silages in aquafeeds depends on determination of its apparent digestibility coefficients (ADC). This work aimed to determining the ADC of crude protein and amino acids of acid silage (AS), biological silage (BS) and enzymatic silage (ES) for juvenile Nile tilapia (94.5 ± 12.7 g). The ADCCP was: 92.0%, 89.1% and 93.7% for AS, BS and SE respectively. The average ADC of amino acids was: 91.8%, 90.8% and 94.6% for AS, BS and ES respectively. Results encourage the use of AS, BS and ES to partially replace protein sources in balanced diets for neotropical fish.

Comparison of Performance and Economics of a Long-yearling and Calf-fed System

AbstractPerformance and economics of calf feeding and feeding long-yearlings was compared from University of Nebraska research conducted from 1996 to 2004. All calves in these studies were spring born and purchased the subsequent fall. The heaviest calves (292 ± 5 kg) were placed into the feedlot and fed an average of 168 d (calf-feds), whereas the lighter calves (239 ± 5 kg) were placed into a long-yearling system consisting of corn residue grazing followed by summer grazing before entering the feedlot for finishing. Long-yearlings were fed in the feedlot for an average of 90 d. At the beginning of the finishing period, long-yearlings were 143kg heavier than calf-feds (P < 0.01). Although daily DMI was greater for long-yearlings (P < 0.01), calffeds consumed more total DM during finishing (P < 0.01). Long-yearlings had greater ADG compared with calf-feds during finishing (P < 0.01); however, calffeds were 18.7% more efficient (P < 0.01). Long-yearlings were 38kg heavier (P < 0.01) than calf-feds and had 24kg heavier hot carcass weight (P < 0.01). Quality grade was not affected by production system (P > 0.10); however, calffeds had 0.15cm greater fat thickness (P < 0.01). Long-yearlings were more profitable than calf-feds (P < 0.01) due to lower feed cost (P < 0.01), yardage (P < 0.01), and initial animal cost (P < 0.01). However, long-yearlings had higher interest cost (P < 0.01) and total cost (P = 0.02). Long-yearlings produced greater final BW leading to an improvement in profitability compared with calffeds.

Breeding objectives for Targhee sheep1

Breeding objectives were developed for Targhee sheep under rangeland production conditions. Traits considered were those for which EPD were available from the US National Sheep Improvement Program and included direct and maternal effects on 120-d weaning weight (WW and MM, respectively); yearling weight (YW); yearling fleece weight, fiber diameter, and staple length; and percent lamb crop (PLC), measured as the number of lambs born per 100 ewes lambing. A bioeconomic model was used to predict the effects of a change of 1 additive SD in EPD for each trait, holding all other traits constant at their mean, on animal performance, feed requirements, feed costs, and economic returns. Resulting economic weightings were then used to derive selection indexes. Indexes were derived separately for 3 prolificacy levels (1.41, 1.55, and 1.70 lambs/ewe lambing), 2 triplet survival levels (50 and 67%), 2 lamb pricing policies (with or without discounting of prices for heavy feeder lambs), and 3 forage cost scenarios (renting pasture, purchasing hay, or reducing flock size to accommodate increased nutrient requirements for production). Increasing PLC generally had the largest impact on profitability, although an increase in WW was equally important, with low feed costs and no discounting of prices for heavy feeder lambs. Increases in PLC were recommended at all 3 prolificacy levels, but with low triplet survival the value of increasing PLC eventually declined as the mean litter size increased to approximately 2.15 lambs/ewe lambing and above. Increasing YW (independent of WW) increased ewe maintenance costs and reduced profitability. Predicted changes in breeding values for WW and YW under index selection varied with lamb pricing policy and feed costs. With low feed costs or no discounts for heavy lambs, YW increased at a modest rate in association with increasing WW, but with high feed costs or discounting of heavy lambs, genetic trends in WW were reduced by approximately 50% to constrain increases in YW. Changes in EPD for MM or fleece traits generally had smaller effects on profitability than changes in PLC, WW, and YW. Two indexes designed to address current rangeland production conditions (low forage costs and discounting of heavy feeder lambs) or more intensive and integrated production with retained ownership and value-based marketing of lambs (higher forage costs and no discounting of heavy lambs) were anticipated to meet the needs of most Targhee producers.

Assessment of the Practical Potential of Bambara (Voandzeia subterrenea Thouars) Waste for Weaner Pigs

Twenty four Large White x Landrace weaner pigs averaging 6.72+0.04kg at 8th week of age were used in a 56 days feeding trial to assess the feeding potential of Toasted Bambara Waste (TBW) fed at 0, 5, 10 and 15% levels. The diets were formulated to contain 18% crude protein and 2800kcal ME/kg. The pigs were randomly allocated to four treatments according to weight, sex and litter-mates with three replicates per treatment and two pigs per replicate. Results show that the final body weight of pigs on the control diet (0% TBW) were comparable (P>0.05) to those of pigs on the 10% TBW levels. The efficiency with which the pigs on 10% level of TBW utilized the diet was not significantly different from those of pigs on the control diet (P>0.05). The economy of feed conversion showed that the lowest feed cost per kg live weight gain was observed for pigs on the 10% TBW diet. Haematological evaluation further revealed that pigs on the 10% TBW diet had the highest red blood cells count which differed significantly (P<0.05) from the other treatments. It is concluded that weaner pigs can tolerate diets with up to 10% level of toasted bambara waste with better performance and cost benefits.

Optimising dietary energy and amino acid levels in the diets of naked neck broilers for growth, nutrient utilisation and immune response in a hot climate

AbstractThe need for a critical amino acid (AA) profile for growth, immune response and N utilisation of naked neck broilers during summer was studied. Day‐old naked neck chicks (n = 198) from a single hatch were distributed into 24 groups (four dietary regimens (DRs) with six replicates each) having eight birds in each replicate. The first diet was based on crude protein (CP) and metabolisable energy (ME) (13.40 MJ) as per NRC recommendations (DR1). In the second diet, the CP content was reduced through supplementation of synthetic AAs to achieve critical AA contents as suggested by NRC with 13.40 MJ ME (DR2). In the third diet critical AAs were supplemented to achieve their level at 108% of NRC with 12.6 MJ ME (DR3), while in fourth diet critical AA concentration was reduced to 94% (DR4) of NRC with 12.6 MJ ME to match the ratio of ME to AA concentration as that of NRC (1994). Diets were formulated separately for starter (0–3 weeks) and finisher (3‐6 weeks) phases. A metabolism trial was conducted at the third week of age. At 3 and 6 weeks of age eight birds (four of each sex) per treatment were killed to study the growth of immune organs (Bursa of Fabricius, thymus and spleen). Immune response was studied at the fourth week of age. During the starting phase, the birds fed DR1 and DR2 having 13.40 MJ ME kg−1 diet had higher body weight (P &lt; 0.044) gain (P &lt; 0.048) and better feed conversion ratio (FCR) (P &lt; 0.001) as compared to DR3 and DR4 (12.6 MJ ME kg−1 diets). However, better (P &lt; 0.001) CP efficiency (CP intake kg−1 gain) and lower feed cost kg−1 gain (P &lt; 0.001) was recorded in DR4. A similar trend was also observed during the finisher phase. Dietary regimens had no effect on dry matter (DM) metabolisability, N intake or output and N retention. There was no difference in the weight of immune organs (bursa, thymus and spleen) between dietary treatments at either 3 or 6 weeks of age. The cell mediated and humoral immune response was also not different between the NRC and modified NRC levels. Copyright © 2007 Society of Chemical Industry

Performance and carcass yield of barrows fed dried poultry waste as a replacement for palm kernel cake

Performance characteristics and carcass yield obtained from barrows (castrated male pigs) fed a diet in which dried poultry waste (DPW) totally replaced palm kernel cake (PKC) was investi-gated. The DPW diet was inferior in terms of total weight gained (30.8 kg as opposed to 34.2 kg for the PKC diet). The daily weight gain and efficiency of feed utilization were also better in the PKC diet (610.70 g versus 550 g and 0.318 versus 0.288, respectively). The carcass yield is 43.57 and 41.39 kg in the PKC and DPW diets, respectively. However, the DPW diet showed a lower feed cost per kilogram of the diet and gave higher monetary returns per kilogram of meat produced. Also this study revealed that using DPW to fatten pigs up to 60 kg resulted in a net saving of N196.00 per pig. The inclusion of DPW at this level in the growers’ ration for pigs could therefore be beneficial in terms of reduction of feed cost and higher returns per kilogram of meat produced.

Evaluation of Performance, Organ Characteristics and Economic Analysis of Broiler Finisher Fed Dried Rumen Digesta

A 28-day feeding trial involving 264, 5-week old Hubbard broilers was carried out in a completely randomized design to evaluate the performance, organ characteristics and economic analysis of broiler s fed dried rumen digesta (DRD) at dietary levels of 0, 5, 10 and 15% respectively. Feed intake of the groups on varying dietary levels of dried rumen digesta were significantly (P 0.05). The lower feed cost per kilogramme meat produced on dried rumen digesta diet suggest that the material is economically viable alternative. Furhter research is necessary to investigate the biosafety of dried rumen digesta.

The Productivity of White Shrimp at Intensif Fishpond in Tulang Bawang Lampung

Since its introduction on the beginning of 2000’s the cultures of white shrimp (Litopenaus vannamei) in Indonesia highly developed. This species which is originated from Central America has successfully triggered shrimp cultures in Indonesia due to its high productivity. White shrimp has several advantages such as high survival rate (SR), high density, high disease resistance, low feed conversion ratio (FCR) as well as lower feed cost. The increase of worldwide market demand caused shrimp farmers to increase their productivity by means of increasing initial stock. Objective of this experiment was to study the productivity of white shrimp cultured intensively including yield, SR, FCR, and average daily gain (ADG). Method of this research was case study of white shrimp culture in Tulang Bawang, The Province of Lampung. Data were taken from 40 of 0.5 ha-shrimp ponds cultured intensively. Results showed that the average productivity was 7,615 kg per pond with initial stock of 503,735 postlarvae, SR of 84%, FCR of 1,4 and ADG of 0,15 gram per day. Key words: productivity of white shrimp, intensive pond

An Economic Efficiency of Feed Allocation for Broiler Production in Poultry Farms of Arbil Governorate

Feed is the major cost of broiler production. Hence, one of the main opportunities for increasing profit, is to lower feed costs per unit of gain, through rational allocation of this input in the production process, consequently, it increases the product and simultaneously it reduces the gap between local production and consumption. Also, knowledge of relationship between feed and product provides the producers by the useful indicators, which help them in decision making process. Aiming to this object, the current study estimated the production function of broiler, applying the (OLS) method, using observations of the sample collected from 36 private farms in Arbil Governorate. The Cobb-Douglas production function was selected, relying on the sensibility of the results, statistical and econometrical criteria. So, the required economic functions have been derived and used along with market prices of feed and product, in order to achieve some practical conclusions and recommendations. The important one is that, the level of feed had not been extended to the point that maximizes the profit according to the results of the study

Keratinase technology: from feather degradation and feed additive,to prion destruction.

Abstract A bio-process called thermophilic anaerobic digestion that converts poultry waste into biogas energy was developed in our laboratory. During operation, feathers in the waste were completely degraded. This observation prompted a series of studies that have led to new technology and commercial developments. A feather-degrading bacterium was discovered and isolated. An enzyme called keratinase capable of hydrolysing the feather protein keratin was purified. The gene encoding this enzyme was isolated and sequenced. Genetic modification enabled the over expression of the gene in the parent strain as well as in other Bacillus strains. Scale-up fermentation, first in 150 l and then in 50 kl fermentors, made the mass production of the enzyme possible. Subsequently, in application research, keratinase was shown to partially hydrolyse feathers and convert them into a digestible feed protein. When supplemented as a feed additive on standard diet, the enzyme promoted chicken growth by improving dietary protein digestibility. Ifcommercially developed, keratinase can lower feed cost, increase poultry meat yield, and upgrade the utilization of less digestible protein feedstuffs. From an environmental point of view, keratinase has the potential to reduce waste nitrogen excretion by farm animals. More recently, keratinase was found to be able to degrade prion protein that is believed to cause transmissible spongiform encephalopathies (TSE) including ‘mad cow disease’, sheep scrapie, deer chronic wasting disease and human Creutzfeldt–Jakob disease. This discovery indicated the potential use of keratinase in a new enzymatic process to destroy prion protein and possibly prevent TSE, in a cost-effective and environmentally friendly manner. To test and to develop the enzymatic process, a prion-like surrogate protein (PSP) has been developed as a safe bio-marker. The combination of keratinase and PSP can provide a useful toolbox for TSE prevention. Based on the keratinase platform technology and its applications, BioResource International (BRI), a biotechnology company, was founded to serve the poultry and animal industries.

Effect of Replacing Soybean Meal with Soya Waste and Fish Meal with Ensiled Shrimp Waste on the Performance of Growing Crossbred Ducks

Two experiments were conducted with growing crossbred Super-Meat ducks at the experimental duck farm of Cantho University to evaluate the effects of reducing the proportion of soybean meal (SBM) in a broken rice (BR)-SBM mixture and providing soya waste (SW) ad libitum (Expt. 1), and reducing the proportion of fish meal (FM) in a BR-FM mixture and supplying ensiled shrimp waste (ESW) ad libitum (Expt.2). Both experiments included five treatments, with three replicates and ten growing ducks per replicate. In Expt.1, the five diets were based on BR and five levels of SBM, with SW offered ad libitum. The control diet (SBM25) consisted of 75% BR and 25% SBM, and the other four treatments included SBM levels of 20% (SBM20), 14% (SBM14), 8% (SBM8) and 0% (SBM0) mixed with BR to 100%, and with SW ad libitum. In Expt. 2, the control diet consisted of 86% BR and 14% FM, and the other dietary treatments had FM levels of 11% (FM11), 8% (FM8), 4% (FM4) and 0% (FM0) mixed with BR, and with ESW ad libitum. In Expt. 1, total intakes of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) were higher for birds given SW (p<0.001). Total CP intake was highest on the SBM20 diet, and lowest on the SBM0 diet (p<0.001). Lower daily gain (DG) was found for the SBM0 diet (p<0.01). Carcass weights were higher on the control treatment, with the lowest values on the SBM0 diet (p<0.001). Gizzard weights were higher on diets with high intakes of SW (p<0.05). In Expt. 2, birds with high intakes of ESW (FM4 and FM0) had lower (p<0.01) daily intakes of DM. The total CP intakes declined (p<0.001) with higher intakes of ESW. The highest DG were for the control and FM11 diets, while the lowest value was for diet FM0 (p<0.001). The poorest feed conversion ratio (FCR) was for the FM0 treatment (p<0.01). Lower weights of carcass and breast muscle were found on the FM0 diet (p<0.001). Feed costs per kg gain were only slightly different between diets. However, the lowest feed cost was for ducks on the SBM0 and FM11 diets in Expt.1 and Expt. 2, respectively. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 6 : 825-834)

The effects of meal transition diets on nursery pig growth performance in a commercial environment (2005)

A total of 2,016 pigs (initially 12.6 lb and 18 ± 2 d of age) were used in a 28-d growth assay to evaluate the current feed-budget allocations for SEW, Transition, and Phase 2 diets fed in meal form in a commercial environment. Pigs were allotted to one of six treatments, with a variety of feed budgets: 1) pelleted diets with 1 lb/pig of SEW diet (6.7% plasma) and 3 lb/pig of Transition diet (2.5% plasma); 2) pelleted diets with 0.5 lb/pig of SEW diet (6.7% plasma) and 1 lb/pig of Transition diet (2.5% plasma); 3) meal diet with 2 lb/pig Transition diet (2.5% plasma); 4) meal diet with 4 lb/pig of Transition diet (2.5% plasma); 5) meal diet with 2 lb Transition diet (4% plasma); and 6) meal diet with 4 lb Transition diet (4% plasma). After the allotted amount of feed was distributed to the pens as described in the budget, all treatments were fed 12 lb/pig of a Phase 2 meal diet, and then a Phase 3 meal diet for the duration of the trial. From day 0 to 10 and for the overall period, the pigs fed the pelleted SEW and Transition diets grew faster, and had better feed efficiency, lower removal rates (culls), and greater margin over feed cost than did the pigs fed the meal-based Transition diets. For pigs fed the pelleted SEW and Transition diets, pigs fed 1 and 3 lb, respectively, had better ADG and F/G for the period d 0 to 10 after weaning, better F/G for the period d 0 to 28, lower feed cost per lb of gain, and greater margin over feed than pigs fed 0.5 and 1 lb, respectively, of SEW and Transition diets. The current recommendations of providing weanling pigs 1 lb/pig SEW diet and 3 lb/pig Transition diet optimized growth and profitability in this production system.

Influence of Replacement of Concentrate by Beer By-product on Performance of Broilers in Central Vietnam

In an attempt to lower feed costs of small-holder broiler production in the area of Hue City, Central Vietnam, we replaced part of the commercial concentrate component of the diet by locally available wheat brewing by-product. There were three experimental diets containing either 5, 10 or 15% brewing by-product. The three diets were fed on five small-holder farms to groups of 20 broilers each. The results show that beer by-product enhanced growth and improved feed efficiency. Slaughter carcass traits and the weights of breast and drumstick were enhanced by the feeding of beer by-product. The inclusion of 10% beer by-product in the diet increased the antibody titre against Newcastle disease when the birds were aged 9 weeks, but not when they were aged either 4 or 12 weeks. It is concluded that substitution of brewers' wheat for part of th e concentrate component can render broiler diets less expense and more efficient.

Effects on overall performance of feeding commercially grown pigs less or more than their lysine requirement in early and late finishing (2004)

A total of 1154 gilts (PIC L337 × C22, initially 72.3 ± 1.7 lb) were used to determine effects on subsequent growth performance of feeding less than or at the estimated lysine requirement for optimal growth and feed efficiency in early finishing (70 to170 lb). From d 0 to 27 and d 27 to 55, pigs were fed a diet containing 2.75 and 2.25 g lysine/Mcal ME, respectively, which was less than their estimated requirement. Pigs fed at their estimated requirements were provided diets containing 3.30 and 2.75 g lysine/Mcal ME from d 0 to 27 and 27 to 55, respectively. Pigs within each early finishing treatment subsequently were fed less than, at, or more than (1.75, 2.25, 2.75 g lysine/Mcal ME, respectively) the estimated lysine requirement from 170 lb to slaughter at 255 lb. In early finishing (70 to 170 lb), pigs fed at the estimated lysine requirement had improved (P<0.003) ADG, feed efficiency, and income over marginal feed costs (IOMFC) compared with those of pigs fed less than their estimated dietary lysine requirement. But pigs fed less than the lysine requirement had lower (P<0.001) feed cost per pound of gain. In late finishing (170 to 255 lb), ADG, feed efficiency, feed cost per pound of gain, and IOMFC improved (quadratic, P<0.006) with increasing dietary lysine, and were optimized at the estimated lysine requirement (2.25 g lysine/Mcal ME). Pigs fed lysine-deficient diets in early finishing had improved (P<0.005) feed efficiency and feed cost per pound of gain in late finishing, compared with those of pigs fed adequate lysine in early finishing. Carcass lean measures improved (quadratic, P<0.02) with increasing dietary lysine in late finishing. Feed costs per pound of gain from d 0 to 104 were increased (P<0.001) when feeding increased dietary lysine in early finishing, and were not affected (P>0.17) by late finishing dietary treatment. Overall IOMFC was not affected (P>0.62) by the lysine-to-calorie ratio (g lysine/Mcal ME) fed in early finishing (70 to 170 lb), and increased (linear, P<0.02) with increasing lysine in late finishing (170 to 255 lb). But increasing dietary lysine from 2.25 to 2.75 g lysine/ Mcal ME in late finishing did not improve (P>0.89) d 0 to 104 IOMFC. Due to compensatory improvements in late finishing feed efficiency and feed cost per pound of gain, pigs fed diets less than biological requirements in early finishing, and subsequently fed at the estimated lysine requirement in late finishing, had lower (0.145 vs. 0.148 ± $0.001, P<0.03) feed cost per pound of gain, and similar IOMFC (79.62 vs. 79.13 ± $ 0.62 per head, P>0.70) to that of pigs fed at the estimated dietary lysine requirement throughout finishing. Understanding the biologic and economic dynamics of over- and under-feeding lysine in early (70 to 170 lb) and late (170 lb to 255 lb) finishing provides guidance in formulating cost-effective feeding strategies. This study suggests that, as long as lysine requirements are being met in mid-late finishing (170 lb to slaughter), feeding slightly less than the lysine requirement for optimal performance in early finishing reduces feed costs without sacrificing overall IOMFC.; Swine Day, 2004, Kansas State University, Manhattan, KS, 2004

Biotechnological advances in finfish hatchery production: a review

It has been estimated that about 80 billion juveniles were required for the 1998 production level of 20 million metric tonnes of finfish. Increasing demand for aquaculture products has prompted researchers to produce more and better quality juveniles. This paper reviews recent relevant literature and mainly summarizes information from a workshop held in Hawaii in December 1999 to review the status of fry production and discuss current technical advances in live and inert feed production. Although hatchery technology follows similar protocols worldwide, modifications are made to meet specific needs. Feeding regimes and culture systems are modified to improve fish survival and lower production costs. Selecting appropriate feed, maintaining strict hygienic conditions versus manipulating natural conditions, and choosing a suitable water exchange system are good examples. Rotifers ( Brachionus spp.) and brine shrimp ( Artemia spp.) nauplii are the main live food items for early life stages of the major finfish species, with inert feed provided at a later stage. Superintensive rotifer culture (up to 190,000 individuals/ml) using algal paste has been studied to improve cost-effectiveness of hatchery production. While Artemia has potential use as an efficient delivery system for antibiotics, great variation in its nutritional content from different sources, the need for further studies on nutritional requirements of larvae, and decreasing supplies due to increased demand are important factors in calculating cost-effectiveness of this form of live feed. Studies on live feed production should continue, but reduced demand for live feed was recommended. In studies on larval digestive enzymes in fish and inert feed formulations, formulated feed has the potential to replace live feed earlier in the life cycle than is common in current practice. Formulated feeds used as a delivery system for substances such as hormones and vaccines would be an asset to hatcheries. Greater understanding of the roles of microbial processes in culture systems is expected to lead to major breakthroughs in hatchery production. Management of the microbial community may positively affect live feed production, larviculture, and inert feed application. Understanding changes in the microbial community in response to feed could result in dual benefits of lowering feed costs and preventing spread of diseases. Further research was recommended. Finally, there was general agreement expressed that information exchange among researchers and the aquaculture industry is essential for effective research efforts and application of these results to production.

USING FULL FAT SOYBEAN IN BROILER DIETS AND ITS EFFECT ON THE PRODUCTION AND ECONOMIC EFFICIENCY OF FATTENING

This study aimed to test new diet formulae based on full fat soybean destined to Arbor Acres broilers fattening. A sample of 520 chickens, divided into two groups was used: M-Group, fed with a diet containing maize, soybean meal, oil and fish meal and FFS Group, fed with another diet mainly containing full fat soybean and other components. The diets have been elaborated in three alternatives for each fattening stage: starter, grower and finisher. During the fattening, the main parameters have been recorded and compared between the two groups: daily and total live weight gain, daily and total food consumption, as well as feeding and fattening costs. A number of 8 fattened chickens were slaughtered and we also determined slaughter output, the components of carcass, the chemical composition of chicken meat and the ratio between saturated and unsaturated fatty acids. The FFS plot recorded higher fattening performances, that is a higher daily and total gain, a lower food consumption, but also lower feeding and total costs in comparison with the other group. We have noticed that FFS diet assured an increased crude protein percentage inside chicken meat and a more convenient ratio between the fatty acids, in favour of the unsaturated ones, resulting to a high meat and fat quality.

Dietary protein level and natural food management in the culture of blue (Litopenaeus stylirostris ) and white shrimp (Litopenaeus vannamei ) in microcosms

The effect of dietary protein level and natural food management on the production parameters of blue and white shrimp, as well as on water quality, was evaluated in a microcosms system (plastic pools simulating aquaculture ponds). Two experimental trials were carried out in the facilities of DICTUS, University of Sonora, Northwest México. Treatment with low protein diet (LP) consisted of a low protein input (diet with 250 g kg−1 crude protein) through the culture period; treatment with high protein diet (HP) consisted of a high protein input (diet with 400 g kg−1 crude protein) through the trial, and finally treatment VP consisted of an adjustment of protein input (diets with 250, 350 or 400 g kg−1 crude protein), depending on the abundance of biota (zooplankton and benthos) in the system. Each species responded differently to the treatments. For blue shrimp, low protein input resulted in the lowest final body weight (12.9 ± 0.6 g) and biomass (696.0 g pool−1). Survival and feed conversion ratio were similar in the three treatments. For white shrimp, the best growth, biomass and food conversion ratio were obtained in the low protein input treatment. Water quality parameters such as nitrate, ammonia and organic matter during the two trials, were better for LP and VP treatments. White shrimp seems to have lower protein requirements than blue shrimp. For the blue shrimp culture, adjusting protein input according to natural food abundance (zooplankton and benthos) in the system, seems to be advantageous because of the possibility of getting a production similar to that obtained with a high protein input through the farming period, but at lower feed cost, and with a lower environmental impact. It is concluded that a high protein input through the whole farming period is not the best feeding strategy for any of the two species.

Performance of Weaner Lambs on Conventional Feeds or Supplemented with Mango Seed Kernel (Mangifera indica) and Babul Pods Chuni (Acacia nilotica) under Intensive Production System

Twenty four weaner lambs, eight each of Marwari, Patanwadi and Merino×Patanwadi breeds (9.9 to 10.8 kg) were randomly divided into two dietary treatments on body weight basis Viz. T1-conventional (Maize-38%, GN Cake-25%, Rice Polish-24%, Jaggery solution-10%, Mineral mixture-3%) and T2-supplemented non conventional group (GN Cake-25%, Rice Polish-14%, Mango seed kernel-25%, Babul Pods chuni-23%, Jaggery solution-10%, Mineral mixture-3%). The Jaggery solution was prepared by mixing 6.5 kg Jaggery and 3.5 kg water. The average final body weight at the end of the experiment was recorded to be 19.33±0.76 and 19.72±0.8 kg in conventional and non-conventional groups, respectively. The total dry matter intake (DMI) during the entire experiment period was recorded to be 89.56±5.19 and 95.08±1.06 (kg/head) and 532.83±9.94 and 566.75±10.49 g/d in conventional and non- conventional groups, respectively. The body weight gain and body measurements did not influenced by diet. The ration effect was found to be significant when the DMI was expressed in terms of g/d. The crude protein (CP) and digestible crude protein (DCP) intake/head and per kg gain observed during experiment under conventional and non-conventional treatment group did not differ from each other. However, the total digestible nutrients (TDN) intake per kg gain was significantly (p<0.05) higher in supplemented non-conventional group. The intake values of DCP and TDN were more or less in agreement with Indian Council Agricultural Research (1985) recommendations. The estimated total feed cost (Rs./animal) for experimental lambs was 274.16±8.57and 242.67±5.10 in conventional and non- group, respectively. The non-conventional group had significantly (p<0.05) lower feed cost (11.6%). The return as percent of feed cost and feed cost/kg dressed weight were 92.89±5.58 (%) and Rs. 35.40±1.11 and 122.61±5.06 (%) and Rs.30.47±1.71 in conventional and non-conventional group (p<0.05), respectively which is the reflection of significantly lower total feed cost incurred during feeding in non-conventional group. Lambs fed non-conventional based diet had similar live weights as those fed conventional diets but costed less money to achieve those weights. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 10 : 1469-1474)