Janaína Maria Batista de Sousa

Effect of the levels of calcium and particle size of limestone on laying hens

This experiment was conducted to evaluate the effect of levels of calcium (Ca) and particle size of limestone (LS) for laying hens. It was used 216 Dekalb White laying hens at 25 to 49 weeks of age in a completely randomized design in a 3 × 2 factorial arrangement, composed of three levels of calcium (3.92, 4.02 and 4.12%) and two particle sizes of limestone (thin - 0.60 mm; and thick - 1.00 mm), resulting in 6 treatments with six replicates of six birds. There was no significant effect of levels of calcium and limestone particle size neither of the interaction calcium × particle size for feed intake, egg weight, specific gravity, shell thickness, shell percentage, Haugh unit, calcium and phosphorus digestibility and percentage of digestive tract. Production, mass, conversion by mass and conversion by egg dozen had their best results with 4.12% of calcium in the diet. Percentage of gizzard and feed intake observed at 3:00 p.m. improved as limestone granulometry improved from 0.60 to 1.00 mm. There was an interaction effect among calcium level and limestone granulometry for breaking strength of tibia, bone density, length of the small intestine and feed intake at 6:00 a.m.; 9:00 a.m., 12:00 p.m., 6:00 p.m. and 9:00 p.m., respectively. It is recommended the addition of 4.12% of calcium and limestone in the thick granulometry (1.00 mm) for a better performance of commercial laying hens. More studies are needed to elucidate the mechanisms involved in the alteration of nutritional behavior of laying hens in response to changes in the levels of calcium and in the granulometry of limestone in the rations.

The efficacy of Mentha arvensis L. and M. piperita L. essential oils in reducing pathogenic bacteria and maintaining quality characteristics in cashew, guava, mango, and pineapple juices.

This study evaluated the ability of the essential oil from Mentha arvensis L. (MAEO) and M. piperita L. (MPEO) to induce ≥5-log reductions in counts (CFU/mL) of E. coli, L. monocytogenes, and Salmonella enterica serovar Enteritidis in Brain-Heart Infusion broth (BHIB) and cashew, guava, mango, and pineapple juices during refrigerated storage (4±0.5°C). The effects of the incorporation of these essential oils on some physicochemical and sensory parameters of juices were also evaluated. The incorporation of 5, 2.5, 1.25, or 0.625μL/mL of MAEO in BHIB caused a ≥5-log reduction in counts of E. coli and Salmonella Enteritidis after 24h of storage; but only 5μL/mL was able to cause the same reduction in counts of L.monocytogenes. The incorporation of 10μL/mL of MPEO in BHIB caused a ≥5-log reduction in counts of E. coli, Salmonella Enteritidis, and L. monocytogenes after 24h of storage; smaller reductions were observed in BHIB containing 5, 2.5, and 1.25μL/mL of MPEO. Similar reductions were observed when the MAEO or MPEO was incorporated at the same concentrations in mango juice. The incorporation of MAEO or MPEO at all tested concentrations in cashew, guava, and pineapple juices resulted in a ≥5-log reduction in pathogen counts within 1h. The incorporation of MAEO and MPEO (0.625 and 1.25μL/mL, respectively) in fruit juices did not induce alterations in °Brix, pH, and acidity, but negatively affected the taste, aftertaste, and overall acceptance. The use of MAEO or MPEO at low concentrations could constitute an interesting tool to achieve the required 5-log reduction of pathogenic bacteria in cashew, guava, mango, and pineapple fruit juices. However, new methods combining the use of MAEO or MPEO with other technologies are necessary to reduce their negative impacts on specific sensory properties of these juices.

Methionine+cystine requirements for light and semi-heavy replacement birds fed mashed or pelleted feeds.

The objective of this study was to reevaluate the requirements of Methionine+cystine (met+cis total) of light (L) and semi-heavy (SH) pullets at 5 to 11 weeks of age considering the physical shape of the feeds and the performance in the 22 to 40 week period, the laying phase. A total of 1,120 laying pullets (560 lightweight and 560 semiheavy) in a randomized completedesign in a 5 ×2 ×2 factorial scheme with 20 combinations consisting of five total Met+Cys levels (0.56; 0.60; 0.64; 0.68 or 0.72), two physical shapes (mashed and pelleted) of the feed and two lines (Dekalb White and Bovans Goldline) each with four replications of 14 birds each. The basal rations were supplemented with DL-Met. (99%) to provide five total Met+Cys levels according to the recommendations of the Brazilian literature and the line handbook. The experimental feeds of the growing period were isonutritive in ME (2,900 kcal/kg), CP (17%), Ca (1,000) and available P (0.450), containing total Met+Cy levels of 0.56; 0.60; 0.64; 0.68 and 0.72, while in the laying period, a single diet with 2,850 kcal/kg ME, (16%) CP, (3.70%) of Ca and (0.340%) of available P was fed. The semiheavy birds performed better compared to the light birds. The pelleted feed provided better total and daily feed intakes compared to the mashed feed. In the laying phase, the Met+Cys levels affected production, egg weight and mass and conversion to egg mass. The levels of Met+Cys and the physical shape of the feed over the laying period affected the subsequent performance of the birds in the laying period. The light line performed best. Levels of 320 and 364 mg Met+Cys daily are recommended for light and semi-heavy birds, respectively.

Sensory and volatile profiles of monofloral honeys produced by native stingless bees of the brazilian semiarid region

Monofloral honeys produced by stingless bees M. subnitida Ducke and M. scutellaris Latrelle in typical flowering of the Brazilian semi-arid Ziziphus juazeiro Mart (juazeiro), Croton heliotropiifolius Kunth (velame branco) and Mimosa arenosa willd Poir (jurema branca) were characterized in relation to volatile and sensorial profile. It identified 11 sensory descriptors and 96 volatile compounds. It was noticed a strong effect of flowering in sensorial profile and volatile of honeys. Juazeiro honey stood out with a higher characteristic aroma, taste sweet, caramel flavor and levels of aromatic aldehydes; jurema honey has been described with herb and beeswax aroma and the presence of sulfur compounds and ketones; volatile acids associated with acid taste, medicinal taste and clove aroma characterized the velame branco honey. These results demonstrate that the knowledge of the sensory and aroma profile of these honeys can contribute to characterization of its floral and geographical identity.

Predicting and Modelling the Growth of Potentially Pathogenic Bacteria in Coalho Cheese

Coalho is a semihard medium- to high-moisture cheese produced in various states in the northeastern region of Brazil. This study was conducted to predict the growth kinetics (maximum growth rate, Grmax) of Escherichia coli, Listeria monocytogenes, Salmonella, and Staphylococcus aureus using the ComBase predictor with various combinations of temperature, pH, and water activity (aw) in commercial Coalho cheese samples. The growth of two antibiotic-resistant derivative strains of L. monocytogenes (parental strains ATCC 19115 and ATCC 7644) and S. aureus (parental strains ATCC 13565 and ATCC 19095) was measured in commercial Coalho cheese samples during 14 days of storage as a function of the initial contamination level (3 and 5 log CFU/g) and storage temperature (7.5 and 12°C). The highest Grmax values predicted by ComBase under the various conditions of temperature, pH, and aw were for L. monocytogenes (0.006 to 0.065 log CFU/g/h) and S. aureus (0.003 to 0.048 log CFU/g/h). The Grmax values predicted by ComBase for E. coli and Salmonella were 0.007 to 0.026 and 0.008 to 0.041 log CFU/g/h, respectively. An experimental challenge in Coalho cheese revealed that the populations of all tested antibiotic-resistant derivative strains of L. monocytogenes and S. aureus increased (>0.5 log CFU/g) by day 14 of storage at 7.5 or 12°C. L. monocytogenes and S. aureus had higher Grmax values in cheese samples stored at 12°C than those stored at 7.5°C. The ComBase growth predictions under the temperature, pH, and aw conditions in commercial Coalho cheese samples were generally fail-safe for predicting the growth of L. monocytogenes and S. aureus in the actual product. These results indicate that Coalho cheese has pH and aw characteristics that allow the growth of E. coli, L. monocytogenes, Salmonella, and S. aureus. These cheeses are typically stored at temperatures that do not prevent the growth of these bacteria.