Estela Kobashigawa

Aflatoxin B1 residues in eggs of laying hens fed a diet containing different levels of the mycotoxin

The present study was carried out to evaluate the excretion of aflatoxin B1 residues in eggs of young laying hens fed aflatoxin B1-contaminated rations for 8 weeks. To this end, 96 twenty-week-old hens were randomly distributed into four experimental groups (24 birds per group) and given rations containing either 0 (controls), 100 μg, 300 μg or 500 μg aflatoxin B1/kg feed. Egg aflatoxin B1 residues were determined by thin layer chromatography; two samples per treatment per week were used for analysis. Egg production and average egg weights were not affected (p < 0.05) in the groups receiving aflatoxin B1-contaminated rations. Residues of aflatoxin B were detected only in the eggs 1 of hens given 500 μg/kg feed, at levels that ranged from 0.05 to 0.16 μg/kg (average: 0.10 μg/kg). The results indicate that the feed to eggs aflatoxin B transmission 1 ratio was approximately 5000:1, emphasizing the importance of controlling aflatoxin levels in rations for laying hens.

Mycoflora and Co-Occurrence of Fumonisins and Aflatoxins in Freshly Harvested Corn in Different Regions of Brazil

Natural mycoflora and co-occurrence of fumonisins (FB1, FB2) and aflatoxins (AFB1, AFB2, AFG1 and AFG2) in freshly harvested corn grain samples from four regions of Brazil were investigated. Fusarium verticillioides was predominant in all samples. Analysis of fumonisins showed that 98% of the samples were contaminated with FB1 and 74.5% with FB1 + FB2, with toxin levels ranging from 0.015 to 9.67 μg/g for FB1 and from 0.015 to 3.16 μg/g for FB2. Twenty-one (10.5%) samples were contaminated with AFB1, seven (3.5%) with AFB2 and only one (0.5%) with AFG1 and AFG2 Co-contamination with aflatoxins and fumonisins was observed in 7% of the samples. The highest contamination of fumonisins and aflatoxins was observed in Nova Odessa (SP) and Várzea Grande (MT), respectively. The lowest contamination of these mycotoxins was found in Várzea Grande and Nova Odessa, respectively.

Níveis de lisina digestível para frangos de corte machos no período de 37 a 49 dias de idade

One thousand and fifteen commercial male broilers from 37 to 49 days of age were used to evaluate different digestible lysine levels. A completely randomized trial was used, with five treatments (0.90, 0.95, 1.00, 1.05 and 1.10% of digestible lysine, respectively), seven repetitions and 35 experimental units, with 29 birds each. Lysine levels were added in isoenergetic (3,250 kcal of ME/kg) and isoproteic (18% of CP) corn and soy meal rations. Weight gain, feed intake, feed:gain ratio, carcass characteristics and cuts, body composition and nutrient deposition were measured. Digestible lysine levels influenced the feed:gain ratio, with decreasing linear effect. Quadratic effect was observed due to lysine levels used on carcass characteristics, cuts and abdominal fat deposition. The variable chemical composition of the carcass, empty body and mineral matter showed quadratic effect on the digestible lysine levels. The digestible lysine levels had no effect on the chemical composition of blood and offal fractions. However, evidences of linear increase in the protein deposition of carcass and empty body due to the increase in the digestible lysine level were observed. Considering performance, the digestible lysine level should be 1.10% or higher.

Lisina digestível e zinco quelado para frangos de corte machos: desempenho e retenção de nitrogênio na fase pré-inicial

Two experiments were carried out to evaluate different levels of digestible lysine (0.90; 1.00; 1.10; 1.20; e 1.40%) combined with zinc chelate (43 and 253 ppm) to male broiler. The considered periods were: initial phase - performance (1 to 11 days old) and nitrogen retention (1 to 7 days old). A randomized block experimental design in a 5 × 2 factorial arrangement was used. In performance assay, 7 replications and 15 birds per experimental unit was used. In the digestibility essay, 6 replications 6 birds for experimental unit were used. The diets contained 2.960 kcal/kg ME and 21.0% crude protein. In the initial phase, there was no digestible lysine × zinc chelate interaction on performance study, however a quadratic effect of digestible lysine on final weight, weight gain, relative weight gain and crescent linear effect in feed intake was observed. In feed: gain ratio did not differ with digestible lysine level and zinc chelate in the diet. In the performance, the better digestible lysine level for broiler raised in concrete floor is 1.19%. From 1 at 7 days old, there was no influence of the combinations of digestible lysine and zinc chelate on nitrogen balance. The nitrogen retention linearly increased as digestible lysine increased in the diet. This response coincided with linear increase of weight gain and feed: gain ratio. A digestible lysine requirement for male broilers from 1 to 7 days old is equal or bigger then 1.40% for male broiler from one at seven days of age.

Níveis dietéticos de lisina digestível para frangos de corte machos no período de 1 a 11 dias de idade: desempenho e composição corporal

An experiment was carried out to evaluate digestible lysine requirement for male broilers chicks of Ross line from 1 to 11 days old. A total of 1050 one day old male chicks were fed with five isoenergetic (2,950 kcal ME/kg) and isoproteic (23% CP) diets, with digestible lysine levels of 1.12, 1.17, 1.22, 1.27 and 1.35%. A completely randomized bloc design was used with seven replications of 30 birds per experimental unit. A comparative slaughter technique was conducted to determine body nutrients depositions. A decreasing linear effects in final weight, weight gain, relative weight gain and feed intake were observed suggesting a probable amino acid excess in diet. The body chemical composition did not differ among birds, except for blood and offal ashes content, whish shown a quadratic response to digestible lysine levels in the diets. A decreasing linear response was observed for carcass water deposition. The best digestible lysine level for broilers from 1 to 11 days old must be equal to or lower than 1.12%, however further researches must be conducted with lower levels.

Dietary levels of lysine for male broilers from 23 to 36 days of age: performance and body composition

One thousand and fifty (1,050) Ross male broilers from 23 to 36 days of age were used to evaluate the dietary effects of levels of lysine. It was used a random block design with 5 levels of digestible lysine (0.95; 1.00; 1.05; 1.10 and 1.15%). Each level was applied to seven replicates and the experimental unit was composed of 30 birds. Diets were offered in seven replicates and the experimental unit was represented by 30 birds. Weight gain, feed intake, feed conversion, carcass traits, cut yields, composition and deposition of body nutrients were evaluated. The concentration of 1.09% of digestible lysine optimized performance without significant effects on feed intake. Carcass traits and cut yields had no significant differences among levels of lysine. On the other hand, there was a quadratic effect on carcass weight, which was the best at the level of 1.07% of digestible lysine. On crude protein content of the empty body, the best response was observed at the level of 1.10% of dietary lysine. This same level corresponded to a quadratic response in the deposition of water from carcass and empty body. The level of digestible lysine for better performance, chemical composition and body nutrient deposition in broilers from 23 to 36 days of age is between 1.07 and 1.10%.

Characterization of aflatoxigenic and non-aflatoxigenic strains of Aspergillus section Flavi isolated from corn grains of different geographic origins in Brazil

Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B1, while 47.2% aflatoxins B1 and B2. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson’s correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB1 and AFB2, but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.

Lisina digestível e zinco orgânico para frangos de corte machos na fase de 22 a 42 dias de idade

The dietary effects of digestible lysine and chelate zinc for male broiler chickens from 22 to 42 days of age were evaluated in two experimental assays. A complete randomized block experimental design in a 5 × 2 factorial, with five lysine levels (0.841, 0.876, 0.997, 1.022 and 1.030%) and two levels of zinc (43 and 243 ppm) was used. In the first assay, it was used 900 birds with initial average weight 957.4 g distributed in experimental units with 30 birds and three replications and in the second assay, 180 broilers with initial average weight 866.22g split in plots with 3 birds and six replications were used. The characteristics evaluated were performance, cut yield and body composition (1st assay), nitrogen balance and apparent digestibility of diets (2nd assay). There was an interaction among levels of lysine and zinc for weight gain, feed conversion, ingested dry matter and energy balance. Yields of breast, thigh and drumstick had linear increases in response to increments in the level of digestible lysine in the diet. The best performance was obtained for level 0.997% of digestive lysine (or 1.134% total lysine) and level of 43 ppm zinc. For higher cut yields, the recommended level of digestible lysine has to be at least 1.002% (or 1.139% total lysine), regardless to the levels of chelate zinc. Greater inclusion of zinc in diets for broiler from 22 to 42 days of age does not improve the utilization of dietary lysine and increases body fat deposition.

Relação entre atividade de plasmina e frações de caseína durante o armazenamento do leite longa vida

The objective of this study was to correlate the plasmin activity and the concentrations of casein fractions in ultra-high-temperature (UHT) milk manufactured in a dairy plant in the State of Sao Paulo, Brazil. Raw milk was pasteurized (72-76 oC, 15-20 seconds), followed by direct steam injection into the milk (132-136 oC, 34 seconds), then homogenized and aseptically packaged into cartons. Four replicates of the UHT milk were analyzed for the plasmin activity and casein fractions after 10, 30, 60, 90 and 120 days of storage. Plasmin activity significantly increased in the UHT milk during storage and was negatively correlated with the concentration of αs1-casein. Plasmin is resistant to milk sterilization by the UHT process, and increases proteolysis of the UHT milk as a consequence of αs1-casein degradation.

Digestible lysine and organic zinc for male broiler from 1 to 11 days of age: performance and body composition

This study evaluated levels of digestible lysine and organic zinc for male Ross strain broilers from 1 to 11 days of age. It was used 1,050 chicks distributed in randomized block design, in 5 × 2 factorial scheme, with seven repetitions of 15 birds per experimental unit. The dietary concentrations of digestible lysine were 0.90; 1.00; 1.10; 1.20; and 1.40% combined with 43 and 253 ppm zinc chelate. The diets contained 2,965 ± 18 kcal/kg of apparent metabolizable energy (AME) and 21.48 ± 0.18% of CP. It was determined chemical composition, protein, lipid, mineral and water depositions on carcass and empty body. There was no interaction among the factors digestible lysine and organic zinc. Effect of zinc concentration increase was observed on greatest deposition of body fat, indicating that there is interference in lipid metabolism of the birds in the studied phase. The most pronounced effects resulted from the dietary inclusion of lysine. There was a linear effect on reconstituted body weight as a response to the increase of dietary lysine, which suggests equal or superior requirement to the greatest studied level. However, the deposition of water and protein on the carcass had a quadratic increase, characterizing higher muscle mass accumulation up to the levels 1.25 and 1.27 of this amino acid in the diet. Considering the studied strain, broiler chickens from the first to the 11th days of age require 1.28 ± 0.01% of digestible lysine, according to the deposition of muscle mass.