Effects of methionine supplementing on intestine, liver and uterus morphology, and on positivity and expression of calbindin-D28k and TRPV6 calcium carriers in laying quails in thermoneutral conditions and under thermal stress

Abstract

23The aim of this study was to provide support for the performance, localization and expression of the 24 epithelial calcium transporter channels, calbindin-D28k (Calb) and TRPV6, and of the morphology of the 25 digestive and reproductive system of laying quails under heat stress, and with methionine 26 supplementation. Therefore, the present study characterized the positivity (immunohistochemistry) and 27 expression (real-time PCR) of calcium channels (Calb and TRPV6) in the kidneys, intestine and uterus of 28 504 laying quails that were submitted to different methionine supplementation (100, 110 and 120%) and 29 temperatures (20, 24, 28 and 32ºC). The animals under thermal stress had lower villus height, villus:crypt 30 ratio, and goblet cell index in the duodenum and jejunum, fewer secondary and tertiary uterine folds, 31 smaller hepatic steatosis, and increased number of distal convoluted renal tubules (CT) positive to Calb 32 (protein), and increased positivity in proximal CTs. The deleterious effects of heat stress were minimized 33 with methionine supplementation for the following variables: duodenal crypts, number of goblet cells of 34 the jejunum, number of uterine folds, decreased Calb positivity in intestines and kidney, increased 35 positivity of Calb in the uterus and increased TRPV6 gene expression in the kidney. Calcium transporters 36 were altered due to less need for calcium absorption and reabsorption due to more calcium available with 37 the supplementation, increasing egg production and quality. Methionine supplementation further 38 increased intestinal villus absorption area and height, increased steatosis, decreased Calb positivity in the 39 intestine and kidney, increased uterine positivity and Calb expression, and increased TRPV6 expression 40 in the uterus under thermoneutrality. This is the first study that describes the gene and protein expression 41 of calcium transporters in the intestine, kidney and uterus of laying quails, and concludes that the use of 42 methionine supplementation is justifiable in order to partially reverse the deleterious effects of thermal 43 stress on the production. 44 45 46 3 47 65Methionine, classified as an essential amino acid [9], is also the first limiting factor in poultry 66 feed, and is essential for the maintenance, growth, production, and development of feathers [10]. In 67 addition to the productive responses obtained with methionine supplementation in laying hens, studies of 68 the morphological analyses of the laying digestive and reproductive system of broilers and light birds 69 indicate favorable quantitative and qualitative changes, such as an increase in egg mass by 10%. [11,12], 70 decreased laying fat [13], increased eggshell thickness [14], and increased intestinal villi [15], which 71 provide and technically justify the improvement in zootechnical indexes of these animals with methionine 72 use [15][16][17][18]. 73Evaluating the existing literature [15][16][17][18], diets supplemented with methionine at levels above 74 NRC (Nat...

Effect of prenatal ambient temperature on the performance physiological parameters, and oxidative metabolism of Japanese quail (Coturnix coturnix japonica) layers exposed to heat stress during growth

“…The temperature selected for inducing heat stress has been previously reported to affect bird metabolism 20 , 21 . As expected, in the current study, high ambient temperature reduced the egg laying performance of quail mothers.…”

“…During this period, bird development and egg laying rate were monitored daily. At 98 days of age, 40 female quail with a mean body weight of 157.25 g and an egg laying rate of 85% were divided and subjected to two environmental conditions: thermoneutral (23 °C and 60% relative humidity) ( n = 10) and heat stress (continuous exposure to 32 °C 20 , 21 and 60% relative humidity) ( n = 30). During the experimental period, birds were kept in individual cages with ad libitum access to feed and water.…”