Médica Veterinaria Zootecnista, magister en Producción Animal y doctora en Nutrición y Producción Animal, docente universitaria e investigadora. Mi actividad investigativa esta relacionada con el análisis nutricional de alimentos y aditivos nutricionales, producción avícola, porcina piscícola y cunicola, además de la evaluación de calidad de producto final (carne y huevo). Competente en el establecimiento de planes de manejo; en liderar procesos y organizar proyectos productivos, académicos e investigativos y con formación ética, social y amplio sentido de responsabilidad. Mi principal línea de interes es el área de producción y nutrición de monogástricos y la evaluación de la claidad de productos de origen animal.
Mayra Diaz Vargas
LÍNEAS DE INVESTIGACIÓN: Producción y Nutrición de Monogástricos - Nutrición animal - Tecnología, Higiene y Seguridad Alimentaria
FACULTAD: Ciencias Agropecuarias
NIVEL DE FORMACIÓN: Doctorado
Using of Okara in diets for growing broilers
Fecha de publicación: 04/10/2018
This study aimed to evaluate the effects of okara inclusion in diet for growing broilers on performance, carcass yield, blood and bone variables, quality and lipid oxidation of meat and economic viability. For that, 575 Cobb 21-days-old male broilers were distributed in a completely randomized design with four levels of okara inclusion (25, 50, 75 and 100 g of okara/kg diet) and a control group with five replicates and 23 birds each. There was no difference (P>0.05) in function of okara levels on the performance variables, carcass yield, bone variables and serum triglycerides, calcium and phosphorus at 42 days old. Serum cholesterol levels showed a quadratic response (P<0.05), in which the lowest value estimated was 65.3 g of okara/kg of diet. Okara can be included in diets for broilers up to the level of 100g/kg without affecting the performance, carcass yield, bone variables and lipid oxidation of meat. However, the best economic results were observed up to 50g of okara/kg of diet.
Más información ⇨
Propolis residue inclusion in the diet affects digestive enzyme activity in broiler chickens
Fecha de publicación: 01/05/2017
This study investigated the effects of the inclusion of solid propolis residue (PR) from alcoholic propolis extraction in the diets of broiler chickens from 1 to 21-d of age on their performance, intestinal morphology, and digestive enzyme activity. 405 male chicks were distributed in a completely randomized design with five treatments (inclusion of 0, 1, 2, 3 and 4% PR in the diets), and three replications with 27 birds each. The birds were fed experimental diets from 1 to 21-d of age and basal diet from 22 to 42-d of age. Feed intake (from 1 to 21-d and 1 to 42-d of age) decreased linearly with increasing levels of PR inclusion (P < 0.05). Dietary inclusion of PR did not affect intestinal morphology at 7 and 21-d of age (P > 0.05). Pancreatic amylase activity presented a quadratic response at 7 and 21-d of age, with its lowest activity estimated at 2.45 and 1.91% PR inclusion, respectively. At 7-d of age, trypsin activity decreased linearly, whereas chymotrypsin activity varied quadratically, with its activity estimated at 2.06% PR inclusion. Intestinal maltase activity varied quadratically with lowest activity predicted at 1.57% PR inclusion at 21-d of age. The dietary inclusion of solid propolis residue of propolis decreases feed intake in broilers and modulates their intestinal and pancreatic enzyme activity.
Más información ⇨
Dehydrated citrus pulp in broiler diets
Fecha de publicación: 13/06/2018
The objective of this study was to evaluate the effects of citrus pulp in diet for broilers on weight of gastrointestinal organs, intestinal morphometry, and quality and lipid oxidation of broiler meat during the storage time. A total of 966 Cobb male broiler chicks were fed six increasing levels of dietary citrus pulp (0%, 2%, 4%, 6%, 8%, and 10%) with seven replications of 23 birds each. The inclusion of citrus pulp in the diet of broilers from 1 to 21 d of age did not significantly affect organ weight and intestinal morphology (P > 0.05). However, the citrus pulp can be used up to 10% inclusion in diets for broilers from 1 to 42 d of age, without impairing broiler performance, carcass yield, intestinal morphometry, and meat quality. For lipid oxidation, samples of thigh were used in a 6 × 4 factorial design (six dietary levels of citrus pulp and four storage periods) with four replications. In the treatments with 10% citrus pulp, the phenolic compounds present in the by-product led to a delayed and reduced oxidation.
Más información ⇨
By-product of passion fruit seed (Passiflora edulis) in the diet of commercial laying hens
Fecha de publicación: 15/06/2016
This study evaluated the effects of the inclusion of the by-product passion fruit seed (BPFS) in the diet of laying hens on performance, blood variables, quality, and lipid oxidation in eggs. A total of 384 Hy-line W36 layers (32 wk old) were distributed in a completely randomized design, with six treatments (control, 2.5%, 5.0%, 7.5%, 10.0%, and 12.5% inclusion of BPFS), eight replicates and eight birds each. The productive performance was evaluated for three cycles of 28 d each. There was no difference (P > 0.05) in egg production and feed conversion. However, feed intake showed increased linearly (P < 0.05). The egg weight, egg mass, percentage of eggshell, eggshell thickness, and Haugh unit did not differ (P > 0.05); however, the specific gravity of eggs increased (P < 0.05). Total cholesterol and blood triglycerides decreased linearly (P < 0.05). To evaluate the lipid yolk oxidation, a 6 × 5 × 2 factorial design (six levels of BPFS × five storage periods × two temperatures) was used. There was an interaction (P < 0.05) among the levels of BPFS, time, and storage temperature with the lowest oxidation level of 12.5% when eggs were refrigerated. The BPFS can be included at a level up to 5.0% without compromising bird performance and 12.5% for egg quality, and this level reduced yolk lipid oxidation.
Más información ⇨
By-product of passion fruit seed (Passiflora edulis) in the diet of broilers
Fecha de publicación: 26/07/2017
Two experiments were performed to determine the chemical composition of by-product of passion fruit seed (BPFS) and to evaluate the performance, blood variables, carcass yield, meat quality, and oxidation of broilers fed diets containing increasing levels of BPFS. In experiment 1, a total of 60 twenty-one-day-old Cobb male broilers were distributed in a completely randomized design, with two treatments (reference feed and test diet) and five replicates of 6 birds each. Energy content in BPFS was 3945 kcal kg−1 of apparent metabolizable energy corrected for nitrogen balance and 10.68% crude protein. In experiment 2, a total of 864 one-day-old male Cobb broilers were distributed in a completely randomized design, with six treatments (control, 2.5%, 5.0%, 7.5%, 10%, and 12.5% BPFS) and six replicates of 24 birds each. Feed conversion linearly worsened (P < 0.05). At 21 d of age, blood triglyceride levels linearly decreased (P < 0.05). At 42 d, there was a linear decrease in villus height in the jejunum as the inclusion of BPFS increases. Meat quality was not affected by the different levels of BPFS. For lipid oxidation, used samples of thigh in a 6 × 3 factorial design (six levels of addition of BPFS and three storage periods) with four replications. In the treatments with 5% BPFS, the phenolic compounds present in the by-product led to a delayed and reduced oxidation. In conclusion, from 1 to 21 d and 1 to 42 d, BPFS can be used up to 5% in broiler diets without harming the parameters evaluated.
Más información ⇨