RESUMEN
The aim of the present study was to evaluate the effects of marine microalgae (Dunaliella salina) as a food additive on biogas (BG), methane (CH4), carbon monoxide (CO), and hydrogen sulfide (H2S) production kinetics, as well as in in vitro rumen fermentation and the CH4 conversion efficiency of different genotypes of maize (Zea mays L.) and states of forage. The treatments were characterized by the forage of five maize genotypes (Amarillo, Montesa, Olotillo, Tampiqueño, and Tuxpeño), two states of forage (fresh and ensiled), and the addition of 3% (on DM basis) of microalgae (with and without). The parameters (b = asymptotic production, c = production rate, and Lag = delay phase before gas production) of the production of BG, CH4, CO, and H2S showed an effect (p < 0.05) of the genotype, the state of the forage, the addition of the microalgae, or some of its interactions, except for the time in the CO delay phase (p > 0.05). Moreover, the addition of microalgae decreased (p < 0.05) the production of BG, CH4, and H2S in most of the genotypes and stages of the forage, but the production of CO increased (p < 0.05). In the case of fermentation characteristics, the microalgae increased (p < 0.05) the pH, DMD, SCFA, and ME in most genotypes and forage states. With the addition of the microalgae, the fresh forage from Olotillo obtained the highest pH (p < 0.05), and the ensiled from Amarillo, the highest (p < 0.05) DMD, SCFA, and ME. However, the ensiled forage produced more (p < 0.05) CH4 per unit of SFCA, ME, and OM, and the microalgae increased it (p < 0.05) even more, and the fresh forage from Amarillo presented the highest (p < 0.05) quantity of CH4 per unit of product. In conclusion, the D. salina microalga showed a potential to reduce the production of BG, CH4, and H2S in maize forage, but its effect depended on the chemical composition of the genotype and the state of the forage. Despite the above, the energy value of the forage (fresh and ensiled) improved, the DMD increased, and in some cases, SCFA and ME also increased, all without compromising CH4 conversion efficiency.
RESUMEN
High environmental temperatures cause heat stress in ewes, resulting in thermoregulatory problems. In this study, the thermoregulatory responses of Blackbelly adult ewes (G1, n = 14) and female lambs (G2, n = 7), during the summer under tropical conditions, in southern Mexico were analyzed. Different physiological variables and skin temperatures (ST) of the ewes were recorded. Breathing frequency (BF) values were similar between groups at 116.73 ± 33.598 bpm (G1) and 113.661 ± 34.515 bpm (G2) (p > 0.05). In the case of skin elasticity (SE), there were no significant differences between the time of day and the age of the ewes (p > 0.05). Significant differences were observed between groups for BF, rectal temperature (RT), and heart rate (HR) values (p < 0.05). All ST values, for both groups, were significantly higher during the afternoon (p < 0.001). In general, all Blackbelly adult ewes and female lambs during the summer present severe heat stress conditions as a result of an increase in physiological constants and ST. It is concluded that all ewes thermoregulate body temperature by modifying different physiological variables to counteract the effect of heat stress.
RESUMEN
Resumen El objetivo de esta investigación fue estudiar la prevalencia de sobrepeso, obesidad y factores asociados en estudiantes de 5° y 6° grado de primaria en dos municipios de la Costa Chica de Guerrero. Se llevó a cabo un estudio descriptivo transversal. Para la recopilación de información se utilizó una báscula digital para registrar las medidas antropométricas y, se aplicó un cuestionario, que incluyó variables relacionadas con hábitos alimenticios, actividad física, tiempo dedicado a ver televisión (TV) y tiempo dedicado a dormir. Se encontró que el 16% de los estudiantes tuvo sobrepeso y 15% obesidad. Hubo mayor riesgo de padecer la enfermedad metabólica en los participantes que ven TV más de 5 h/día (ORns Cl adj = 1.72.IC 95% 1.27-2.34), mientras que comer cuatro o más veces al día tuvo un efecto protector (ORns Cl adj = 0.47, IC 95% 0.31-0.72). En los municipios de Cruz Grande y San Marcos los estudiantes de 5° y 6° de primaria tienen un grado medio de sobrepeso y obesidad; ya que el sedentarismo no es tan marcado y existe la tendencia a practicar el deporte. Se concluye que disminuir el número de horas frente al televisor y la correcta alimentación son acciones que pueden contribuir a la prevención y disminución del sobrepeso y la obesidad en estudiantes de primaria.
Abstract The objective of this research was to study the prevalence of overweight, obesity and associated factors in students of 5th and 6th grade of primary school in two municipalities of the Costa Chica, Guerrero. A crosssectional descriptive study was carried out. For the collection of information, a digital scale was used to record the anthropometric measurements and, a questionnaire was applied, which included variables related to eating habits, physical activity, time spent watching television (TV) and time spent sleeping. It was found that 16% of the students were overweight and 15% obese. There was an increased risk of metabolic disease in participants who watched TV more than 5 h / day (ORns Cl adj = 1.72.IC 95% 1.27-2.34), while eating four or more times a day had a protective effect (ORns Cl adj = 0.47, 95% CI 0.31-0.72). In the municipalities of Cruz Grande and San Marcos, students in grades 5 and 6 have a medium degree of overweight and obesity; since sedentary lifestyle is not as marked and there is a tendency to practice sports. It is concluded that reducing the number of hours in front of the television and the correct feeding are actions that can contribute to the prevention and reduction of overweight and obesity in elementary students.
Resumo O objetivo desta pesquisa foi estudar a prevalência de sobrepeso, obesidade e fatores associados em estudantes da 5ª e 6ª séries do ensino fundamental de dois municípios da Costa Chica de Guerrero. Foi realizado um estudo descritivo transversal. Para a coleta de informações, utilizou-se uma escala digital para registro das medidas antropométricas e aplicou-se um questionário, que incluiu variáveis relacionadas aos hábitos alimentares, atividade física, tempo gasto assistindo televisão (TV) e tempo gasto dormindo. Verificou-se que 16% dos estudantes estavam com sobrepeso e 15% com obesidade. Houve um risco aumentado de doença metabólica nos participantes que assistiram TV mais de 5 h / dia (ORns Cl adj = 1,72.IC 95% 1,27-2,34), enquanto comer quatro ou mais vezes por dia teve um efeito protetor (ORns Cl adj = 0,47, IC 95% 0,31-0,72). Nos municípios de Cruz Grande e San Marcos, os alunos das séries 5 e 6 apresentam sobrepeso e obesidade médios; uma vez que o estilo de vida sedentário não é tão acentuado e existe uma tendência a praticar esportes. Conclui-se que reduzir o número de horas em frente à televisão e a alimentação correta são ações que podem contribuir para a prevenção e redução do sobrepeso e obesidade em alunos do ensino fundamental.
