Effect of temperature on incubation period, embryonic mortality, hatch rate, egg water loss and partridge chick weight (Rhynchotus rufescens)

The aim of this study was to determine the effects of incubation temperature (34.5; 35.5; 36.5; 37.5 and 38.5ºC), on incubation period, embryonic mortality, hatching rate, water loss and chick weight at hatch, using daily incubation of partridge (Rhynchotus rufescens) eggs. The highest hatching percentage was obtained between 35.5 and 36.5ºC. Incubation length and temperature were inversely proportional. Water loss was lower in eggs incubated at low temperatures as compared to high temperatures. There was no difference among incubation temperatures in absolute and relative hatchling weights. Early embryonic mortality increased at low temperatures (<35.5ºC), whereas intermediate and late embryonic mortality increased at high temperatures (>36.5ºC). Our results show that, under conditions of daily incubation of eggs in the same incubator, higher hatching rate can be obtained using temperatures between 35.5ºC and 36.5ºC; incubation temperature is inversely proportional to incubation length, and absolute and relative weights of partridge chicks are not affected by incubation temperature

Models for the analysis of growth curves for rearing tinamous (Rhynchotus rufescens) in captivity

Growth curves models provide a visual assessment of growth as a function of time, and prediction body weight at a specific age. This study aimed at estimating tinamous growth curve using different models, and at verifying their goodness of fit. A total number 11,639 weight records from 411 birds, being 6,671 from females and 3,095 from males, was analyzed. The highest estimates of a parameter were obtained using Brody (BD), von Bertalanffy (VB), Gompertz (GP,) and Logistic function (LG). Adult females were 5.7% heavier than males. The highest estimates of b parameter were obtained in the LG, GP, BD, and VB models. The estimated k parameter values in decreasing order were obtained in LG, GP, VB, and BD models. The correlation between the parameters a and k showed heavier birds are less precocious than the lighter. The estimates of intercept, linear regression coefficient, quadratic regression coefficient, and differences between quadratic coefficient of functions and estimated ties of quadratic-quadratic-quadratic segmented polynomials (QQQSP) were: 31.1732±2.41339; 3.07898± 0.13287; 0.02689±0.00152; -0.05566±0.00193; 0.02349±0.00107, and 57 and 145 days, respectively. The estimated predicted mean error values (PME) of VB, GP, BD, LG, and QQQSP models were, respectively, 0.8353; 0.01715; -0.6939; -2.2453; and -0.7544%. The coefficient of determination (R²) and least square error values (MS) showed similar results. In conclusion, the VB and the QQQSP models adequately described tinamous growth. The best model to describe tinamous growth was the Gompertz model, because it presented the highest R² values, easiness of convergence, lower PME, and the easiness of parameter biological interpretation

Efeito da forma física da ração sobre a porosidade, espessura da casca, perda de água e eclodibilidade em ovos de perdiz (Rhynchotus rufescens) Effect of the physical form of diet on the eggshell porosity and thickness, water loss and hatchability of partridge (Rhynchotus rufescens) eggs

O objetivo do presente estudo foi avaliar se a forma física da ração (farelada e peletizada) afeta a porosidade e espessura da casca, e porcentagem de perda de água e eclodibilidade de ovos de perdiz. Os ovos foram coletados logo após a postura e separados em diferentes intervalos de peso (35-45g, 46-50g, 51-55g, 56-60g e 61-70g), sendo 10 ovos/classe/ração. O número de poros das cascas foi avaliado nas regiões apical, equatorial e basal dos ovos. Utilizou-se um micrômetro digital para a mensuração da espessura das três regiões da casca dos ovos, a partir dos quais obteve-se a espessura média por ovo. Os ovos para avaliação da eclodibilidade e porcentagem de perda de água do ovo até a transferência para o nascedouro (16º dia) foram pesados, desinfectados, incubados (T=35,5&ordm;C e UR= 70%) e transferidos no 16&ordm; dia de incubação para o nascedouro, onde foram mantidos até a eclosão. As análises estatísticas empregadas foram: Análise de Variância e de Correlação, e teste de Tukey 5%. Os dados mostraram que, em perdizes, o número de poros na casca pode variar com a região da casca, peso do ovo e a forma física da ração, e que a ingestão de ração peletizada promove um aumento na espessura da casca dos ovos sem alterar a eclodibilidade e a porcentagem de perda de água dos mesmos durante a incubação.<br>The aim of this study was to determine the effect of the ingestion of meal and pelleted diets on eggshell porosity and thickness, water loss and hatchability percentages of partridge (Rhynchotus rufescens) eggs. The eggs (n=100) were divided into five different weight classes (1: 35-45 g, 2: 46-50 g, 3: 51-55 g, 4: 56-60 g, 5: 61-70 g). Parts from different regions (air space, equator and small end) of each eggshell were analized in order to count pore numbers. Eggshell thickness measurements were carried out after removal of the egg membranes. The eggs used in the analyses of the water loss and hatchability percentages were weighed, desinfected, and then incubated (T=35.5&ordm;C and RH=70%). On the 16th day of incubation, these eggs were transferred to a hatchery maintained at temperature and RH similar to those used in the incubator, where they were kept until hatching. The results showed that the mean number of eggshell pores changed among the three regions of the eggshell and egg weight classes, and also between the physical form of diets. Ingestion of pelleted diet increased eggshell thickness; however, hatchability and water loss percentages remained unchanged

GLUTAMIC ACID IMPROVES BODY WEIGHT GAIN AND INTESTINAL MORPHOLOGY OF BROILER CHICKENS SUBMITTED TO HEAT STRESS

ABSTRACTThe objective of this study was to evaluate the effects of 1% dietary glutamic acid on the body weight, intestinal morphometry, and anti-Newcastle antibody titers of broiler chickens submitted to heat stress. One-d-old male broiler chicks (n=120) were distributed according to a 2 x 2 factorial design with two environmental temperatures (thermoneutral or heat stress) and two diets (with 0 or 1% glutamic acid). Heat stress temperature was constantly maintained (24h/day) 5 ºC higher than the thermoneutral temperature. Diets supplied the nutritional requirements of broilers in the pre-starter (1 to 7d) and starter (8 to 21d) phases. Birds were vaccinated against Newcastle disease on d 7 via eye drop. On days 5, 10, 15, and 20, individual body weight was determined, serum samples were collected from five birds, and duodenum samples were collected from four birds per treatment. Serum anti-Newcastle antibody titers were determined by enzyme immunoassay and transformed into log10. Villus height, crypt depth, and villus: crypt ratio were measured in the duodenum. Data were analyzed by ANOVA. Chronic heat stress negatively affected body weight and intestinal morphometry during the pre-starter and starter phases, but had no effect on antibody titers. Dietary glutamic acid supplementation (1%) improved body weight and intestinal integrity of birds submitted to heat stress when compared with non-supplemented and heat-stressed birds