Zootechnical Performance Research Articles

Dietary garlic (Allium sativum) powder improved zootechnical performance, digestive enzymes activity, and innate immunity in narrow-clawed crayfish (Postantacus leptodactylus)

In this study, the dietary effect of garlic powder (GP) as an herbal supplement on the growth performance, digestive enzymes, innate immunity, and antioxidant capacity of narrow-clawed crayfish, Postantacus leptodactylus, was investigated. In a 90-day feeding trial, the crayfish (N = 360; 25.90 ± 0.41 g initial weight) were fed with a basal diet (control; GP-free) and supplemented diets with three levels of GP (0.5%, 1%, and 2%). The highest final weight and specific growth rate were obtained in the crayfish fed with GP at 1% and 2% (P < 0.05) and the weight gain in GP 2% treatment was 1.6 fold more than the control group. Also, the feed conversion rate and protein efficiency rate were improved in the GP-add groups compared to the control group (P < 0.05). Furthermore, the highest counts of total hemocyte, large-granular cell, and semi-granular cell were recorded in those fed with GP 2% diet. The crayfish fed GP 2% diet showed the highest and lowest body crude lipid (0.24 ± 0.03%) and protein contents (15.95 ± 0.12%), respectively. The highest protease (1.92 ± 0.03 U/ml) and amylase (8.36 ± 0.3 U/ml) activities were detected in the crayfish hepatopancreas fed with GP at 2% (P < 0.05). The highest lysozyme activity (21.26 ± 2.08 U/ml) was observed in the group fed with GP 2% diet, which showed a significant difference from others. Besides, total plasma protein and phenoloxidase activity in the groups fed with GP 1% and GP 2% diets were significantly higher than the control group. Moreover, the activities of superoxide dismutase (79.30 ± 2.19 U/ml) and nitric oxide synthase (4.16 ± 0.05 U/ml) in the plasma were significantly increased in GP 2% diet with respect to the GP 0.5% and control groups (P < 0.05). These findings confirmed the beneficial effects of dietary GP, especially at 2%, on growth rate, physiological performance, innate immunity, and antioxidant capacity in P. leptodactylus.

Mixed culture microorganisms fermented soybean meal improves productive performance and intestinal health of Nile tilapia ( Oreochromis niloticus ) juveniles fed plant‐based diets in a biofloc system

This study aimed to evaluate the effect of plant-based diets containing different inclusion levels (7%, 14%, 21% and 28%) of mixed culture microorganisms fermented soybean meal (FSBM) on the zootechnical performance and intestinal health of juvenile Nile tilapia (Oreochromis niloticus) reared in a biofloc system. The FSBM diets were compared with a positive control diet with fish meal and a negative control diet with no animal protein. All diets were isoprotein (33% CP) and isoenergetic (4300 kcal GE/kg). The design was completely randomized with four replications and the experiment lasted 54 days. Juveniles (1.635 ± 0.198 g) were distributed in 24 tanks (70 L) at a density of seven animals per tank. Fermentation increased probiotic microorganisms count (lactic acid bacteria 4.75 ± 0.21 log CFU g−1 and yeast 3.30 ± 0.54 log CFU g−1) and improved nutritional characteristics of FSBM. In fish fed the diet containing 7% FSBM, growth performance did not differ from fish fed the fish meal diet. FSBM inclusion improved the food efficiency of plant-based diets. The inclusions above 21% of FSBM increased the intestinal villi height. In the inclusion of 28% of FSBM, the goblet cell was higher compared to that of the other plant-based diets. The inclusion of 7% FSBM allows a total replacement of fish meal without compromising the growth performance of the animals.

Does environmental enrichment improve performance, morphometry, yield and weight of broiler parts at different ages?

ABSTRACT The inclusion of environmental enrichment in conventional broiler rearing can increase mobility, bone mass and muscle. This research aimed to evaluate the use of environmental enrichment in the rearing of broilers at different ages and its influence on performance, morphometry, yield and weight of the parts. It was used the completely randomized design in split-plot scheme, being the plots the treatments presence (T1) and absence (T2) of environmental enrichment and the subplots the broiler ages (1, 7, 14, 21, 28, 35 and 42 days), with 56 chicks in each treatment (T1 and T2). Data obtained were analyzed by the linear effect model of fixed effects and compared by Tukey’s test of means. The animals were raised in a controlled environment, divided into four boxes with dimensions: 1.5 × 1.0 × 0.7 m, containing rice straw bed. In T1 a ladder with a perch on top was used, distributed every 1.5 m2. Environmental enrichment used did not influence broiler’s zootechnical performance. Broilers’ morphometric properties, parts weight and body weight increased due to environmental enrichment and, improvement was observed in chicks rearing’s final phase. The environmental enrichment was beneficial for muscle and bone mass gain in the main commercial parts of the chicken carcass, in addition to reducing the allometric coefficient of the breasts in chickens.

Key Performance Indicators of Common Carp (Cyprinus carpio L.) Wintering in a Pond and RAS under Different Feeding Schemes

Overwintering impacts common carp performance, yet the nature of changes is not known. The aim of the study was to compare the zootechnical and key performance indicators (KPI) of Cyprinus carpio wintering in a pond with no supplementary feeding (MCF), in a Recirculating Aquaculture System (RAS) fed typical (30% of protein and 8% of fat) carp diet (AFC), and in a RAS fed high protein (42%) and fat (12%) diet (ABF). The analysis showed that ABF fish had the highest final body weight and the Fulton’s condition factor, as well as the lowest food conversion rate compared with AFC and MCF fish. Histomorphological assessment revealed that MCF fish had thinner skin layers, a depleted population of mucous cells in skin, an excessive interlamellar mass in the gills, and no supranuclear vacuoles in the intestine compared to fish from RAS. At the molecular level, higher transcript levels of il-1β and il-6 transcripts were found in the gills of MCF than in fish from RAS. The transcript level of the intestinal muc5b was the highest in ABF fish. Relative expression of il-1β and il-6 in gills were presumably the highest due to lamellar fusions in MCF fish. Described KPIs may assist carp production to ensure sustainability and food security in the European Union.

Fermentation of Soybean Meal with Lactobacillus acidophilus Allows Greater Inclusion of Vegetable Protein in the Diet and Can Reduce Vibrionacea in the Intestine of the South American Catfish (Rhamdia quelen).

Simple SummaryThere is a demand to replace fishmeal with protein sources of plant origin in fish feeds. Biotechnology strategies, such as fermentation, can improve the bioavailability of plant proteins and decrease the presence of antinutrients, optimizing the results obtained. Fermented soybean meal has already been evaluated for different fish species as a replacement for fishmeal, and there is evidence that it can improve the intestinal health of animals. Lactobacillus acidophilus is a strain used as a probiotic in fish feeding but it remains to be evaluated as a potential fermentation bacterium for feed ingredients. This study aimed to evaluate the effect of diets containing different inclusion levels (0%, 7%, 14%, 21% and 28%) of soybean meal fermented by L. acidophilus (SMFL) on the zootechnical performance and intestinal health of South American catfish juveniles (Rhamdia quelen). The inclusion of SMFL up to 21% in replacement of fish meal did not affect the zootechnical performance of fish and also decreased the concentration of Vibrionaceae bacteria present in the intestine compared to the control group. The results demonstrate that fermentation with L. acidophilus enables greater inclusion of soybean protein in South American catfish diets and promotes the control of intestinal pathogenic bacteria.The objective of this study was to evaluate the effect of diets containing different inclusion levels (0%, 7%, 14%, 21% and 28%) of soybean meal fermented by Lactobacillus acidophilus (SMFL) on the zootechnical performance and intestinal health of South American catfish juveniles (Rhamdia quelen). The experimental design was completely randomized with five treatments and four replications and lasted 56 days. Five isoproteic (39% crude protein) and isoenergetic (4300 kcal of gross energy kg−1) diets were formulated where SMFL was included in replacement of fish meal. Two hundred forty South American catfish juveniles (3.0 ± 0.5 g) were distributed in 20 tanks (70 L) connected in a recirculation aquaculture system. At the end of the experiment, the inclusion of SMFL up to 21% in replacement of fish meal did not affect the zootechnical performance and also decreased the concentration of Vibrionaceae bacteria present in the intestine compared to the control group. The amount of total lactic and heterotrophic bacteria, the enzymatic activity and the intestinal morphometry did not differ between dietary treatments. The results demonstrate that fermentation with Lactobacillus acidophilus enables greater inclusion of soybean protein in South American catfish diets and promotes the control of intestinal pathogenic bacteria.

Effects of dietary various oil sources on zootechnical performance, sexual maturation, whole‐body proximate composition and fatty acid profile of Hediste diversicolor

The ragworm, Hediste diversicolor, is one of the few polychaeta species to present a commercial interest in Iran. In this study, the effects of six oil sources in the diet, namely fish oil (FO), soyabean oil (SBO), canola oil (CAO), corn oil (COO), sunflower oil (SFO) and mixed vegetable oil (MO), on growth, survival, fatty acid profile and biometric measurements of H. diversicolor were conducted during eight weeks. Furthermore, the mean survival rate of H. diversicolor reared on MO (82.93 ± 2.01%) diet, vice versa SGR, WG, Final biomass and PER, was significantly (p < 0.05) lower than that H. diversicolor fed the FO (89.40 ± 3.00%) diet. These findings suggested that MO could supply sufficient essential fatty acids, especially n3 and n6 and effective on zootechnical performance, survival and gonad maturation for juvenile H. diversicolor and should be given to individuals considered for production of dry feeds (and cheaper) of H. diversicolor. The results revealed a higher proportion of n3 HUFA in whole body of H. diversicolor than those in the experimental diets and values of n-3/n-6 in H. diversicolor fed the vegetable diets ranged from 0.13 in the COO diet to 0.21 in the CAO diet, meanwhile the values of n-3/n-6 in H. diversicolor fed the vegetable diets were lower than that obtained for the MO treatment. The FA such as C16:0, C17:0, C18:0 and C20:4ω-6 had a higher concentration in experiment groups than in control. Vegetable oils, especially mix vegetable oils, were economic alternatives to the expensive fish oil used in the H. diversicolor aquaculture industry.

Dehydrated husks and cake of prickly pear (Opuntia ficus-indica) processing for broiler feed: Effects on growth performance, carcass characteristics, and meat quality.

Background and Aim:The potential solution is to use agro-industrial by-products as an unconventional source of raw materials for broiler feed. This study aims to determine the effects of substituting prickly pear (FB; Opuntia ficus-indica) husks for corn and FB seed cake for soybean meal on the production performance, slaughter characteristics, and chemical composition of broiler meat.Materials and Methods:Two hundred day-old chicks of equal sex ratio (1:1) of Big Fast strain, weighing on average 37±2g, were randomly divided into four homogeneous groups of 50 subjects each. Each group was subdivided into 10 packs of five animals, which were banded and numbered. Rations with substitution rates of 0%, 10%, 20%, and 30% of corn and soybean meal by dehydrated husks and FB cake were randomly distributed among the groups.Results:Average daily gains and body weights on 48 days were improved (p<0.05) in 10% and 20% groups, while the 30% group performed identically to the control. Cold carcass yield was optimal in 10% and 20% groups. The liver weight of the experimental groups decreased significantly (p<0.05), while their gizzard weight increased significantly (+24 points). The meat protein rate evolved proportionally to the substitution rate, whereas the fat rate depreciated by up to −1.08 points for the 30% group compared to the control.Conclusion:Incorporating FB processing by-products into broiler feed at rates of 10% and 20% improves zootechnical performance, carcass yields, and the chemical composition of the meat.

The Effect of Natural Additives in Drinking Water on Broiler Production Performances: The Case of Green Anise and Fenugreek

Background: Natural additives supplementation in broiler feed is intended to produce organic meat and minimize the use of chemical drugs that have harmful effects on humans, animals, and the environment. Using locally available plants such as fenugreek and green anise is a much safer and inexpensive alternative Methods: 318 broiler chicks were randomly assigned to three different experimental groups: birds of the first group considered as the control group received an enrofloxacin-based antistress drug; birds of the second group received an aqueous extract of fenugreek; birds of the third group received an aqueous extract of aniseed. Both natural products were used in gradual levels according to the following dosages and duration of treatment:7 grams/liter of water during the period from day15 to day 21 of age; 14 grams/liter of water from day 22 to day 28 and 28 grams/liter of water from day 29 to day 35. For each group, the following zootechnical parameters and carcass characteristics were recorded: mortality rates; Feed Intake (FI), Feed Conversion Ratio (FCR); live weight at slaughter; carcass yield and the weights of the liver, gizzard, and abdominal fat. Findings: Fenugreek was found to have the lowest mortality rate (6,60%) compared to 9,34% for the ”control” group and 8,41% for the ”anise group. Both Fenugreek and aniseed aqueous extracts had similar results to the synthetic antistress on the zootechnical and carcass variables studied. There was no significant difference between the three experimental groups (p> 0,05). Novelty: Supplementation of fenugreek and anise aqueous extracts in broilers’ drinking water has no adverse effect on their zootechnical performance or carcass characteristics. Both natural products could replace synthetic enrofloxacin-based antistress, allowing organic broiler production with reduced costs. Keywords: Trigonella foenum-graecum; Pimpinella anisum; additives; performances; broiler; organic; production

Enhancing effect of Platymonas addition on water quality, microbial community diversity and shrimp performance in biofloc-based tanks for Penaeus vannamei nursery

Biofloc technology (BFT) works by stimulating a microbial community of different metabolic types in order to simultaneously treat pollutants in situ while improving aquaculture. Although microalgae are important autotrophic microorganisms in aquaculture systems, their role in BFT is rarely explored. In this study, Platymonas sp. was selected as a bioaugmentation microalgae for Penaeus vannamei nursery in a BFT system. The experimental group with microalgae additions to 1 × 105 cell·mL−1 every 4 days, were compared to the control group without microalgae addition based on the water quality, biofloc community structure, and enzyme activity measurements. The results showed that the bioaugmentation of Platymonas sp. reduced nitrite‑nitrogen accumulation in rearing water and improved alpha diversity of bacterial communities both in shrimp intestines and in biofloc. Platymonas sp. may improve the microbiological properties of bioflocs by increasing the relative abundance of beneficial bacteria in shrimp aquaculture including Prosthecobacter, Denitromonas, Rheinheimera, Mycobacterium, Roseobacter, Phaeodactylibacter, Cellvibrio and Nannocystis, which help promote nitrification, denitrification, and formation of bioflocs. After 30-day rearing, zootechnical performances of shrimps from the experimental group were significantly higher than those of the control group, including survival rates, specific growth rates and weight gains per week of shrimp each increasing by 63.3%, 7.6% and 53.0%, respectively. Furthermore, microalgal bioaugmentation improved the hepatopancreatic antioxidant status of P. vannamei by significantly increasing the activity of the antioxidant enzymes superoxide dismutase, catalase, and peroxidase in the experimental group. Overall, the results of this study demonstrated that Platymonas sp. addition could simultaneously improving rearing environment and nursery performance for P. vannamei in a biofloc-based system, indicating the important role of microalgae on the BFT application for shrimp nursery.

NSPASES: CAN THOSE EXOGENOUS ENZYMES REALLY CONSTITUTE NATURAL GROWTH COFACTORS IN BROILER CHICKENS?

In the quest to improve public and animal health, white meat is considered to be one of the major causes of antibioresistance identified in medicine, through uncontrolled use of antibiotics in poultry farming as growth promoters (GPA). Thus, this use needs to be reconsidered at large scale. This reconsideration involves the substitution of GPAs by natural alternatives, particularly enzymes degrading non-starch polysaccharides (NSPases) which will allow:1) modulation of the intestinal microbiota, to attenuate the anti-nutritional effects of insoluble NSPs, 2)reduction of the non-digested portion of the substrate and 3) improvement of the zootechnical performance of the chicken. Non-starch polysaccharides contain two main families, namely: water-insoluble NSPs including cellulose and partially water-soluble NSPs. However, despite the fact that these components constitute the major part of cereal dietary fiber, they have an anti-nutritional effect associated with the viscous nature of these polysaccharides and their interaction with the intestinal microflora due to the fact that poultry does not produce enough endogenous enzymes to hydrolyze NSPs. The use of NSPases produced mainly by fungi and bacteria allows counterbalancing the anti-nutritional properties of dietary fibers by increasing the digestibility of starch and improving the zootechnical performance of broilers, particularly the conversion index.Thus, this literature review aims to shed light on the effects of NSPases on the zootechnical parameters of chickens, the intestinal microflora as well as on nutritional digestibility in order to use them as alternatives to GPAs and limit the aggravation of the phenomenon of antibioresistance. This approach is therefore, part of the world famous concept of one world one health and which applies to the design and implementation of programs, policies, legislations and research for which several sectors communicate and collaborate to improve public health outcomes.

Effect of different dietary fibre sources on the zootechnical performance, feeding behaviour and intestinal physiology of growing and finishing pigs

The aim of this study was to determine the effect of different sources of fibre in the diets of fattening pigs on performance, feeding behaviour and intestinal physiology. A total of 60 barrows and gilts (initial body weight 28.4 ± 0.4 kg) were allotted to four dietary treatments: control (CON), lignocellulose (LC), mycelium (MYC) and corn gluten feed (CGF). Diets were calculated to provide balanced available nutrient contents. Including MYC in the diet resulted in an increased average daily gain (P &amp;lt; 0.05) compared to CON and CGF, and improved gain to feed ratio (P &amp;lt; 0.05) compared to LC. Pigs in CON (P &amp;lt; 0.05) ate the fewest but largest meals, whereas treatment CGF (P &amp;lt; 0.05) showed the opposite effect, resulting in the same daily feeder occupation time. Regarding intestinal physiology, in ileum, no differences were observed between the contents of short chain fatty acids (SCFA), lactic acid and biogenic amines. In the colon, MYC showed an increased concentration of acetic acid (P &amp;lt; 0.05) as well as the total content of SCFA (P &amp;lt; 0.05), compared to LC and CGF. Distinct fermentation profiles of ammonia were recorded in ileal and colonic digesta, although contents remained below harmful concentrations. Morphometrical measurements showed differences between the fibre sources LC and MYC, as well as LC and the CON in all investigated gut sections. These results provide evidence that the inclusion of specific dietary fibre sources/contents can positively influence the gut morphology and performance of pigs. However, further studies are needed regarding the mode of action and physico-chemical characteristics of the different fibre sources as a precondition for their successful application in pig diets.

Effect of palm kernel meal (Elaeis guineensis, Jacq, 1763) in the diet on digestive transit and some serum parameters in Nile tilapia (Oreochromis niloticus, Linnaeus, 1758)

As part of the continuation of the thesis work on the valuation of palm kernel cake in the diet of Nile tilapia, a study was carried out from March 7th to April 12th, 2018 at the Aquaculture Research and Development Unit of the University of Lome in Togo. It aims to evaluate the digestive use efficiency of palm kernel cake (PK) in Oreochromis niloticus. So, two lots of 180 male Oreochromis niloticus; juvenile of 57.14 ± 4.43 g and adults of 144.04 ± 7.65 g were each randomly distributed in 9 recirculate system concrete tanks of 600 L, at 20 fish per tank, filled to 250 liters of water. They were fed two weeks with three isoprotein diets (32% crude protein) in triplicate, distributed manually three times a day at 2% of the fish biomass; standard fish feed Raanan (RA) and two diets containing 30% PK untreated (R3) or cooked in water for one hour (R3C). After a 2 days fasting, some fish were fed once again to satiety (8am). Then a sample of 6 fish per lot was euthanized in a clove solution. After blood sampling, the fish were dissected at 0h, 1h, 4h, 8h, 12h and 24h after feeding to measure blood and intestinal parameters. The results obtained show that raw PK is an unpalatable fibrous ingredient but well valued once cooked with a digestive improvement allowing good absorption of food micronutrients in both juveniles and adults. This absorption led to changing in the serum protein level for growth of fish and nitrogenous excretion in the form of urea. The cooking slowed the transit of the food into the digestive tract of tilapia, this can improve zootechnical performance of fish.

Nile tilapia production in polyculture with freshwater shrimp using an aquaponic system and biofloc technology

This study aimed to evaluate the performance of Nile tilapia, freshwater shrimp, lettuce, and watercress in an aquaponic system used in conjunction with biofloc technology. Experimental units consisted of an aquaponic module comprising two containers, one to accommodate vegetables (500 L media-filled bed with gravel) and the other to stock fish and shrimps (1000 L rearing tank). The experiment was carried out in a randomized complete block design with two treatments [an aquaponic system with clear water (ASCW) and an aquaponic system with biofloc technology (ASBFT)] and two blocks (periods). Each treatment had three replicates within each block, totaling six experimental units per block. The final weights of Nile tilapia (ASCW = 546.0 g; ASBFT: 565.0 g), freshwater shrimp (ASCW = 18.82 g; ASBFT: 18.44 g), and vegetable biomass (ASCW: 1.10 kg/m2 of lettuce and 1.57 kg/m2 of watercress; ASBFT: 0.94 kg/m2 of lettuce and 1.98 kg/m2 of watercress) did not differ significantly between the two treatments. Similarly, there were no significant differences between treatments with respect to other zootechnical performance variables of the evaluated organisms. There was, however, a greater (P < 0.05) accumulation of fat in the fillets of Nile tilapia reared in the ASBFT system (0.97%) than in those of fish reared in the ASCW system (0.76%), as well as a lower oscillation of nitrite levels. Therefore, the use of biofloc technology in conjunction with aquaponics facilitated the maintenance of zootechnical performance and contributed to an increase in the fat content of Nile tilapia fillets and better control of nitrite production.

Biodiesel‐derived glycerol as a dietary maize replacement for silver catfish ( Rhamdia quelen ) during the fattening phase

The aim of the present study was to assess the effects of crude biodiesel-derived glycerol on the zootechnical performance, carcass and fillet chemical composition, and blood parameters of silver catfish (Rhamdia quelen) during the fattening phase. A total of 150 adult silver catfish specimens (mean weight 188.89 ± 0.60 g) were distributed in thirty 1000 L-tanks containing a water recirculation system with mechanical filter and biofilter, in a completely randomized design comprising six treatments, 0%, 20%, 40%, 60%, 80% and 100% maize replacement by glycerol, with five repetitions each. The experiment was conducted for 206 days. Silver catfish morphometric parameters were not influenced (p > 0.05) by the glycerol maize replacement, although silver catfish standard length and width exhibited linear improvements (p < 0.05) with the dietary glycerol replacement. Fillet yield was affected (p < 0.05) by glycerol maize replacement, where the 80% replacement treatment led to better fillet yields (46.04%), differing only from the 20% replacement treatment (42.40% fillet yields). The blood plasma levels of glucose, pyruvic glutamic transaminase and triglycerides were influenced by the treatments (p < 0.05). The crude protein of fillet was influenced by the treatments (p < 0.05), where the highest value was observed in 100% glycerol maize replacement. Therefore, crude glycerol derived from biodiesel production is a suitable alternative energy source ingredient for silver catfish during their fattening phase, as it can replace maize in up to 100%.

Effects of a symbiotic on coccidian infestation and zootechnical performances in broilers

Coccidiosis remains an obstacle for the poultry sector worldwide, including Algeria. In the field of food biosecurity, symbiotics are used with the aim of improving zootechnical performance of chickens, and combatting the negative effects of this parasitosis. This study compared two broiler farms with 12,000 chickens of the Arbor Acres strain, where chickens on one farm received supplementation with symbiotics. Weight of 144 animals, mortality, food and water consumption were measured, and consumption (CI) and conversion indices were calculated. For parasitology, droppings were collected and the intestinal contents of 10% of animals were collected. Data showed that at 43 days, the supplemented group had a weight of 2750 g as compared to the control that had a weight of 2630 g, with an average consumption of 4834 g vs. 5087g per animal, CI of 1.62–1.35–0.81 vs. 1.65–1.52–0.89, the conversion index of 1.9 vs. 2.07, and mortality rate of 9.29% vs. 10.37%, respectively. Oocyst excretion was zero at the farm receiving supplementation vs. 0, 100, and 550 OPG in the control group on days 15, 21 and 28, respectively, parasite infestation was 41,600 OPG, 32,800 OPG, and 30,500 OPG vs. 800 OPG, 1,100 OPG and 1,200 OPG, respectively. For prevalence, several species of Eimeria were identified in the control. The means found in this study support the use of symbiotics, and efforts to improve the formula of the symbiotics should yield even better results.

Assessment of Poultry Feed Contamination Level by Aflatoxin B1: Quantification by Two Chromatographic Analysis Methods

Aflatoxin B1 is a mycotoxin that can contaminate a wide feedstuffs variety. Ingestion of contaminated feed by poultry can lead to impaired health and zootechnical performances but also a human diet safety problem related to residues presence in animal origin products. Aflatoxin B1 contamination of poultry feed samples marketed in Dakar city and in peri-urban areas (Gorom, Sangalkam) was studied. A total of 15 samples were collected from Dakar city markets as well as from poultry farms in Gorom and Sangalkam areas. Aflatoxin B1 quantification was performed by high performance liquid chromatography and thin-layer chromatography. HPLC results showed that all samples were contaminated with levels ranging from 0.15 to 22 ppb, 0.099 to 2.05 ppb and 0.099 to 4.95 ppb respectively for Gorom, Sangalkam and Dakar. Only the finishing feed from Gorom had an aflatoxin B1 level above the maximum limit set by regulations. TLC is a suitable method for aflatoxins detection. However, it was associated with overestimation for aflatoxin B1 quantification. Results suggest that poultry feed represents a real source of human diet contamination. In addition, HPLC remains the most reliable quantification technique for quality control.

Zootechnical indices and digestibility in juveniles of tambaqui Colossoma macropomum fed a diet containing particulate maize.

Three experiments were done with different particle sizes of corn feed on its zootechnical performance, passing rate and apparent digestibility of juvenile tambaqui (Colossoma macropomum). In the first, 200 juveniles were used and distributed in 20 tanks (220 L), 10 fish per unit (four replicates). The experimental system used to record passage time was composed of five incubators with 200 L. In the second, 75 juveniles were used per 55 days (three replications). In the third, 75 juveniles were used and distributed in five incubators of 200 L. All experiments were performed randomly. Different linear behavior treatments were observed for apparent digestibility of crude protein; and the smaller particle size (150 μm) had better results digestibility. smaller particle size of the corn had better results, affected the growth performance of tambaqui and the apparent digestibility of crude protein and ether extract. Thus, is recommended that a particle size of 150 μm of corn be used for tambaqui.

FREQUÊNCIA ALIMENTAR DE JUVENIS DO TAMBAQUI (Colossoma macropomum) CRIADOS EM SISTEMA DE RECIRCULAÇÃO

Recirculation aquaculture systems require proper food management, and feeding frequency is one of the most important factors to obtain optimal results in production. The tambaqui Colossoma macropomum presents satisfactory zootechnical performance in Pará State, but research related to its food management in recirculation aquaculture systems are scarce, in view of this, this work aimed to evaluate the zootechnical performance of tambaqui juveniles raised in Recirculation aquaculture systems. A total of 324 tambaqui juveniles with an average initial weight of 24.7 g were used in a recirculation system with three treatments in triplicate, with fish fed two, three and four times a day. The fish were fed with commercial ration with 32 and 36% of crude protein for 40 days and with a feeding rate of 4%. During the experiment were measured: temperature; pH; dissolved oxygen; pH; conductivity; turbidity; salinity, dissolved solids and nitrogen compounds of the system water, and these had a low variation between treatments. The fish fed with higher frequencies had higher final average weight and higher specific growth rate, with this, from the results obtained, it is concluded that the best feeding frequency for tambaqui juveniles is three times a day.

Multienzyme complex in rations containing whole rice bran for newly weaned piglets

Context The feeding of pigs raised in an intensive system has been made, in general, with rations formulated using corn and soybean meal as the main ingredients. Brown rice bran, a by-product of the processing of rice grains for human consumption, presents itself as an alternative for total or partial replacement. Aims The objective of the present study was to observe the effects of including 10% of whole rice bran (WRB), adding 0.02% exogenous multienzyme complex (MC) and changing the levels of metabolisable energy and available phosphorus (ME.aP) together in rations for newly weaned piglets. Methods Digestibility and metabolisability of the rations, as well as zootechnical performance, were evaluated using 24 and 144 animals respectively, distributed in randomised blocks in time, with eight treatments, in a 2 × 2 × 2 factorial scheme. Three repetitions were used in the metabolism essay, with one animal housed per cage, and six repetitions were made in the performance test, with three animals per stall, which was considered the experimental unit. Digestibility and metabolisability coefficients, weight gain and feed intake, as well as feed efficiency, were evaluated. Key results The results showed that the inclusion of WRB reduced the digestibility and metabolisability coefficients of the rations, while the addition of MC provided an improvement in these indexes. The performance test showed that the inclusion of WRB worsened (P &lt; 0.05) the feed efficiency. Conclusions and implications The multienzyme complex improves the digestibility and metabolisability of experimental rations, although it does not influence the performance of piglets in the nursery phase.

Densidade de estocagem no berçário de tilápia em sistema de bioflocos quimioautotrófico

ABSTRACT The nursery phase in tilapia using biofloc technology is important as it increases the predictability of production. However, none studies evaluating the stocking densities of tilapia focused only on the use of an inorganic carbon source to promote the nitrification process as the main way to control nitrogen in the system. This study aimed to evaluate the effect of varied nursery stocking densities, in a chemoautotrophic biofloc system, on water quality, zootechnical parameters, and health of Nile tilapia (Oreochromis niloticus). Fifteen tanks (100 L capacity) containing heaters (28 ±1°C) inoculated with mature bioflocs were used. Seven hundred and fifty tilapia fingerlings (weighing 0.66 ±0.17 g) were distributed in the tanks, in triplicate, so that the densities in the tanks reached 200, 350, 500, 650, and 800 fish m-3. Dissolved oxygen and tilapia growth showed a negative linear relationship with fish density. A positive linear relationship with density was observed for nitrogen compounds, alkalinity, suspended solids, yield, and feed conversion. However, the water quality parameters were appropriate for tilapia and allowed good zootechnical performance irrespective of the fish density. Hematological parameters, fish survival, and uniformity in growth did not alter with densities. Total suspended solids produced by fish biomass showed a quadratic relationship with density, with the highest efficiency of the tanks stocked with 406 fish m-3. It is possible to construct a tilapia nursery in chemoautotrophic biofloc systems with densities reaching up to 800 fish m-3 and yield exceeding 12 kg m-3. But the density of 406 fish m-3 had a better efficiency in solid production by biomass.