Taste processing in Drosophila larvae.

The sense of taste allows animals to detect chemical substances in their environment to initiate appropriate behaviors: to find food or a mate, to avoid hostile environments and predators. Drosophila larvae are a promising model organism to study gustation. Their simple nervous system triggers stereotypic behavioral responses, and the coding of taste can be studied by genetic tools at the single cell level. This review briefly summarizes recent progress on how taste information is sensed and processed by larval cephalic and pharyngeal sense organs. The focus lies on several studies, which revealed cellular and molecular mechanisms required to process sugar, salt, and bitter substances

Caffeine taste signaling in drosophila larvae

The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors

Impacts of willow (Salix babylonica L.) leaf extract on growth, cecal microbial population, and blood biochemical parameters of broilers

ABSTRACT: The investigation examined the use of willow leaf extract (WLE) on broiler chickens, examining carcass characteristics, cecal microbiota, antioxidants, and blood parameters. In 4 groups of 300 chicks, a basal diet was given for 5 wk, and the first treatment was basal diet (C). The diets for the remaining 3 treatments (WLE150, WLE300, and WLE450) contained 150, 300, and 450 mg of willow leaf extract /kg, respectively. The study found that birds fed willow leaf extract supplements had significantly greater body weight (BW), body weight gain (BWG), and enhanced feed conversion ratio (FCR) vs. the control group. Birds fed at 450 mg/kg food showed the greatest growth features, carcass weight, liver weight, lower abdominal fat, better low-density lipoprotein (LDL), and high-density lipoprotein (HDL) concentrations, and highest hematological characteristics. Chickens fed diets supplemented with varied doses of willow leaf extract showed significantly increased antioxidant enzyme activity, with higher amounts of glutathione peroxidase (GPx) activity, superoxide dismutase (SOD), total antioxidant capacity (TAC), and lower malondialdehyde (MDA). However, in the study, birds fed a diet supplemented with 450 mg of willow leaf extract per kg meal showed a significant drop of 13.02%, which found no significant variations in hazardous bacteria (Escherichia coli) across 2 treatments (WLE150 and WLE300). In addition, the study discovered that birds fed with varied doses of willow leaf extract had fewer cecum infections (Staphylococci aureus). We conclude that using willow at a level of 450 mg/kg diet can significantly enhance the BWG, FCR, antioxidant levels and beneficial bacteria activity besides the condition of broiler chicken's general health

Effect of dietary supplementation of betaine and organic minerals on growth performance, serum biochemical parameters, nutrients digestibility, and growth-related genes in broilers under heat stress

Global warming and climate changes have a detrimental impact on poultry production, causing substantial economic losses. This study investigated the effects of incorporating dietary betaine (BT) and organic minerals (OMs) on broilers’ performance as well as their potential to mitigate the negative impacts of heat stress (HS). Six hundred 1-day-old Ross 308 chicks were randomly allocated to 12 experimental treatments with 5 replicates of 10 birds each (5 male + 5 female). The birds were provided with diets containing BT (0 and 2,000 ppm) and OMs (0, 250, and 500 ppm), either individually or in combination, under both thermoneutral and HS-inducing temperatures. The HS conditions involved exposing the birds to cyclic periods of elevated temperature (35°C ± 2°C) for 6 h daily, from 10:00 am to 4:00 pm, starting from d 10 and continuing until d 35. The exposure to HS deteriorated birds’ growth performance; however, dietary BT and OMs inclusion improved the growth performance parameters bringing them close to normal levels. Carcass traits were not affected by dietary supplementation of BT, OMs, HS, or their interaction. Interestingly, while HS led to increased (P < 0.05) levels of total cholesterol, LDL-cholesterol, and hepatic malondialdehyde (MDA), these adverse effects were mitigated (P < 0.05) by the addition of BT and OMs. Moreover, dietary BT supplementation led to elevated serum total protein and globulin concentrations. Cyclic HS did not alter Mn, Zn, and Cu contents in the pectoral muscle. However, the incorporation of OMs at both levels increased concentrations of these minerals. Notably, the combination of 500 ppm OMs and 2,000 ppm BT improved Mn, Zn, Cu, and Fe digestibility, which has been compromised under HS conditions. Cyclic HS upregulated gene expression of interleukin-1β, heat shock protein 70, and Toll-like receptor-4 while downregulated the expression of claudin-1, uncoupling protein, growth hormone receptor, superoxide dismutase 1, glutathione peroxidase 1 and insulin-like growth factor 1. The aforementioned gene expressions were reversed by the combination of higher dietary levels of BT and OMs. In conclusion, the dietary supplementation of 500 ppm OMs along with 2,000 ppm BT yielded significant improvements in growth performance and mineral digestibility among broiler chickens, regardless of thermal conditions. Moreover, this combination effectively restored the expression of growth-related genes even under heat-stress conditions