Effects of a blend of essential oils and overcrowding stress on the growth performance, meat quality and heat shock protein gene expression of broilers

Effects of dietary supplementation of cumin (Cuminum cyminum L.) essential oil on expression of genes related to antioxidant, apoptosis, detoxification, and heat shock mechanism in heat-stressed broiler chickens

This study was carried out to evaluate the impact of cumin essential oil (CEO) supplementation on levels of certain gene expression related to antioxidant, apoptotic, detoxific, and heat shock mechanisms in the breast meat and ileum of heat-stressed broilers. The study was conducted on a 2 × 6 factorial design (heat stress + feed additive) on 600 day-old male broiler chicks for a period of 42 days. From day 7 to 42, although broilers in heat stress groups (HT) were exposed to constant chronic heat stress (36 °C), others were housed at thermoneutral ambient temperature (TN). The chicks in both conditions were fed with 6 experimental diets: C0 (basal diet with no additive), ANTIB (basal diet + 100 mg/kg chloramphenicol), VITE (basal diet + 50 IU α-tocopherol), C2 (basal diet + 200 mg/kg CEO), C4 (basal diet + 400 mg/kg CEO), C6 (basal diet+ 600 mg/kg CEO). The results showed that heat stress upregulated (except for Bcl-2) the genes related to antioxidant, apoptosis, detoxification, and heat shock mechanism. However, cumin essential oil increased the dose-dependently positive effect on certain genes in tissues of the heat-stressed broilers and downregulated (except for Bcl-2) these genes.

Effect of classical music on growth performance, stress level, antioxidant index, immune function and meat quality in broilers at different stocking densities

High-stocking density is one of the factors that can easily cause oxidative stress and inflammatory reaction of broilers. Currently, music therapy has been proposed to help animals relieve stress to some extent. However, it is still unclear whether classical music can alleviate stress in broilers at high stocking densities. Hence, this study aimed to investigate the effects of classical music on growth performance, stress level, antioxidant index, immune function and meat quality of broilers under different stocking densities. A total of 540 one-day-old broilers with similar body weight were randomly divided into 6 treatment groups, with 6 replicates per group, which included two feeding environments (with/without classical music) and three stocking densities (15.5, 17.9, and 20.3 birds/m2), thereby making a 2 × 3 factorial arrangement. The results showed as follows: increasing stocking density decreased the average daily feed intake and average daily gain (ADG), increased feed-to-gain ratio (F/G) and mortality of broilers. Moreover, increased density resulted in an increase in serum corticosterone (CORT) and adrenocorticotropic hormone (ACTH) levels. Increasing stocking density decreased spleen and bursal indices, serum immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) levels. Increasing stocking density elevated serum malondialdehyde (MDA) and decreased catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities. Increasing stocking density decreased serum total protein (TP) levels and increased total cholesterol (TC) and glucose (GLU) levels. Additionally, increasing stocking density decreased the cooking liss of pectoralis and increased the L*24h value of pectoralis. Meanwhile, playing classical music for broilers increased their ADG and decreased F/G, and decreased serum CORT, ACTH, GLU content. In addition, the bursa of Fabricius index, serum IgA and IgG contents as well as the a*24h value of pectoralis was increased under the music therapy. In conclusion, high-stocking density (20.3 birds/m2) harmed the growth performance and health of broilers, and the classical music stimulus ameliorated the negative effects to some extent.

Improving animal welfare status and meat quality through assessment of stress biomarkers: A critical review

Stress induces various physiological and biochemical alterations in the animal body, which are used to assess the stress status of animals. Blood profiles, serum hormones, enzymes, and physiological conditions such as body temperature, heart, and breathing rate of animals are the most commonly used stress biomarkers in the livestock sector. Previous exposure, genetics, stress adaptation, intensity, duration, and rearing practices result in wide intra- and inter-animal variations in the expression of various stress biomarkers. The use of meat proteomics by adequately analyzing the expression of various muscle proteins such as heat shock proteins (HSPs), acute phase proteins (APPs), texture, and tenderness biomarkers help predict meat quality and stress in animals before slaughter. Thus, there is a need to identify non-invasive, rapid, and accurate stress biomarkers that can objectively assess stress in animals. The present manuscript critically reviews various aspects of stress biomarkers in animals and their application in mitigating preslaughter stress in meat production.

Performance, blood biochemistry, carcass fatty acids, antioxidant status, and HSP70 gene expressions in Japanese quails reared under high stocking density: the effects of grape seed powder and meal

Japanese quails reared under high stocking density (SD) were evaluated for the effects of grape seed powder (GSP) and meal (GSM) supplementation on performance, blood biochemistry, thigh and breast muscle fatty acids, antioxidant status, and HSP70 gene expression. We randomly assigned 288 (15-day-old) quail chicks to six treatment groups in a factorial design (2 × 3) with four replicates, involving two density levels [160 cm²/bird (LD) and 80 cm²/bird (HD)] and three feed forms (FFs) [no supplementation, grape seed powder (3% GSP), grape seed meal (3% GSM)]. SD had a significant effect on live weight, but not on weekly feed intake, daily weight gain, and feed conversion ratio. Serum creatinine and aspartate aminotransferase levels were significantly affected by FF and SD × FF (p < 0.05). A high SD reduced the n-3/n-6 ratio of breast muscle and a significant interaction was found between FF (p < 0.001). The SD × FF interaction reduced the Σn-6 ratio in HDM's thigh muscle, whereas in LDM, the ratio increased (p < 0.01). At high SD, neither GSP nor GSM reduced biological markers of oxidative stress (p > 0.05). Compared to GSP, GSM had higher efficacy at reducing HSP70 levels related to high SD levels. Despite this, at high SD, a diet containing 3% of GSP and GSM was not effective in overcoming oxidative stress. Therefore, more studies using different doses of GSM and GSP in quail diets would be beneficial.

Effect of ellagic acid on body weight, nutrient digestibility, fecal microbiota, and urolithin A metabolism in Thoroughbred horses

This study aimed to investigate the effects of ellagic acid (EA) supplementation on body weight (BW), nutrient digestibility, fecal microbiota, blood biochemical indices, and urolithin A metabolism in 1-yr-old Thoroughbred horses. A group of 18 1-yr-old Thoroughbred horses, with an average weight of 339.00 ± 30.11 kg, were randomly allocated into three groups of six horses each (three males and three females). The control group (n = 6) received only the basal diet, whereas test groups I (n = 6) and II (n = 6) were fed the basal diet supplemented with 15 mg/kg BW/d and 30 mg/kg BW/d of EA, respectively, for 40-d. The results showed that test group I and II horses had a significant increase in total weight gain by 49.47% and 62.74%, respectively, compared to the control group. The digestibility of various components in the diets of the test group horses was improved, including dry matter, organic matter, gross energy, neutral detergent fiber, acid detergent fiber, and calcium. Additionally, the digestibility of crude protein and phosphorus (P) in test group II horses increased significantly by 10.96% and 33.56% (P < 0.05), respectively. Moreover, EA supplementation significantly increased the fecal abundance of Firmicutes, Bacteroidetes (P < 0.05), Fibrobacterota, p-251-o5, Desemzia incerta (P < 0.05), and Fibrobacter sp. (P < 0.05), while reducing the abundance of Proteobacteria, Pseudomonadaceae, Pseudomonas, and Cupriavidus pauculus (P < 0.05 or P < 0.01). Fecal samples from test group II showed 89.47%, 100%, and 86.15% increases in the concentrations of acetic acid, valeric acid, and total volatile fatty acids, respectively. In addition, the plasma levels of total protein, and globulin increased significantly in test groups I (7.88% and 11.35%, respectively) and II (13.44% and 16.07%, respectively) compared to those in the control group (P < 0.05). The concentration of urolithin A in fecal and urine samples was positively correlated with increasing doses of EA. These findings suggest that supplemental feeding of EA improved nutrient digestibility, blood biochemical indices, and fecal microbiota in 1-yr-old Thoroughbred horses, promoting growth and development.

Effects of cumin (Cuminum cyminum L.) essential oil and chronic heat stress on growth performance, carcass characteristics, serum biochemistry, antioxidant enzyme activity, and intestinal microbiology in broiler chickens

This study was conducted on 600 one-day-old male broiler chicks, using a 2 × 6 factorial design (ambient temperature, A x feed additive, F), for a period of 42 days. The chicks assigned to different groups were exposed to thermoneutral (TN, 24 ± 1 °C) and constant heat stress (HT, 36 ± 1 °C) conditions, and were only fed on a basal diet, and a basal diet supplemented with either 100 mg/kg chloramphenicol, 50 IU/kg α-tocopherol, or 200, 400, and 600 mg/kg of cumin essential oil (CEO). The results showed that heat stress adversely affected performance and carcass characteristics, and increased both the mortality rate and footpad lesions. Moreover, constant chronic heat stress showed negative effects on serum biochemistry and the intestinal microbiota, increased antioxidant activity in both the plasma and breast meat, and increased counts of the pathogenic microorganisms in the small intestine. On the other hand, dietary CEO supplementation positively affected these parameters. CEO had a slight effect on performance, carcass characteristics, mortality rate and the incidence of footpad lesions. When compared to the control group, it was determined that CEO generally had a positive effect on lipid peroxidation in the plasma and tissues and decreased antioxidant enzyme activity. Furthermore, CEO positively affected serum biochemistry and counts of beneficial microorganisms in the small intestine.

The effect of water shower spray on stress physiology and mortality in broiler chickens subjected to road transportation under the hot and humid tropical condition

This study was performed to investigate the effect of water shower spray on rectal temperature (RT), serum levels of corticosterone (CORT), heat shock protein (HSP) 70 and creatine kinase (CK) in broiler chickens road transported at different times of the day. A total of 320 male broiler chickens (35 days of age) were crated and subjected to either water shower spray (WS) for 10 min or no water shower (control). The WS and control broilers were then loaded into an open truck and transported either from 0900 to 1100 h (29.0 °C and 89.0% RH) (AM) or 1900 h to 2100 h (26.0 °C and 94.0% RH) (PM) with an average speed of 80 km/h. The CORT of AM birds were significantly reduced by WS, but the treatment had negligible influence on the PM group. Transportation during AM significantly elevated RT, CORT and HSP70 compared to the PM group. Water shower spraying of birds before transit significantly reduced RT and HSP70 compared to controls. Neither water shower treatment nor transportation time had a significant on CK and mortality rate of broilers. In conclusion, water shower spray is beneficial to alleviate the physiological stress response in road-transported broilers under the hot and humid tropical environment.

META-ANALYSIS OF PHYTOGENIC ADDITIVES FOR BROILERS

Phytogenic additives have been studied intensively in broiler chickens’ production to substitute growth-promoting antibiotics. However, the comprehensive literature on this topic makes it difficult to understand overall results because there are a noticeable number of studies with conflicting conclusions. While several research studies have shown that phytogenic additives may increment broiler chicken’s performance, others make the opposite evident. This study aimed to organize and understand information through meta-analysis considering a great number of publications and the factors that may interfere in the results of phytogenic additives, evaluating whether phytogenic additives can be used as a performance-enhancing additive for broilers, comparing with the effectiveness of growth-promoting antibiotics. The main factor that interferes in the evaluation of phytogenic additives is the microbiological challenge. Phytogenic additives improved average daily gain (ADG) (P < 0.001) and feed conversion (P < 0.001) regardless of microbiological challenge; however, they were worse compared to antibiotics under higher challenge (P < 0.020). A meta-regression of ADG in function of average daily feed intake confirmed that phytogenic additives increased the feed efficiency of broilers, but with less effectiveness than antibiotics. The blends of phytogenic additives increased the ADG in relation to the isolated use of only one phytogenic additive.

Dietary Encapsulated Essential Oils Improve Production Performance of Coccidiosis-Vaccine-Challenged Broiler Chickens

Simple Summary

The in-feed antibiotics have been banned worldwide, and anticoccidial drugs are also expected to be removed from the formulated, complete feeds. Thus, looking for alternatives to anticoccidials has been on the increase. Essential oils are naturally derived substances containing the aromatic components of herbs and spices and exhibit antibacterial/anticoccidial, antioxidant, and immune modulating-effects, the properties in poultry. These beneficial biological properties of essential oils make them be considered potential anticoccidial agents. Forthermore, encapsulating essential oils is known to be an effective and efficient strategy to slowly release their active components upon passing the gastrointestinal tract. This study was conducted to examine the effects of encapsulated thymol- and carvacrol-based essential oils on productivity and gut health of chickens challenged with high dose of coccidiosis vaccine.

Abstract

The present study was conducted to evaluate the encapsulated essential oils (EEO) as an alternative to anticoccidials using a coccidiosis vaccine challenged model in broiler chickens. A total of 600 one-day-old male broiler chicks were provided with no added corn/soybean-meal-based control diet or diets that contained either salinomycin (SAL) or thymol- and carvacrol-based EEO at 60 and 120 mg per kg of diet. Before challenge at 21 days, each treatment had 10 replicates except for the no-added control group, which had 20 replicates. On day 21, half of the control groups were orally challenged with a coccidiosis vaccine at 25 times higher than the recommended vaccine dose. During 22 to 28 days (i.e., one-week post coccidiosis vaccine challenge), the challenged chickens had a decrease (P < 0.05) in body weight gain and feed intake but an increase in feed conversion ratio compared with the non-challenged, naïve control chickens. However, dietary EEO significantly counteracted (P < 0.05) coccidiosis-vaccine-induced depression in body weight gain and feed intake. Inclusion of dietary EEO linearly decreased (P < 0.05) the concentrations of the volatile fatty acids. Dietary SAL and EEO affected gut morphology in chickens at 20 days post-hatch. Dietary EEO linearly (P = 0.073) increased serum catalase activity as the inclusion level increased. Collectively, our study shows that dietary EEO increased coccidiosis-vaccine-induced growth depression and altered gut physiology in broiler chickens. Our study adds to the accumulating evidence that dietary EEO is proven to be an effective alternative to anticoccidials for broiler chickens.

Effect of supplementation of nicotinamide and sodium butyrate on the growth performance, liver mitochondrial function and gut microbiota of broilers at high stocking density

This study was conducted to investigate the effects of stocking density and dietary nicotinamide (NAM) and butyrate sodium (BA) supplementation on the growth performance, liver mitochondrial function and gut microbiota of broilers at high stocking density. A total of 342, 26-d-old Cobb500 broilers were divided into 5 groups with 6 replicates. Treatments were as follows: (a) Low stocking density (L, 9 birds per cage); (b) High stocking density (H, 12 birds per cage); (c) H + 50 ppm NAM; (d) H + 500 ppm BA; (e) H + 50 ppm NAM + 500 ppm BA (COMB). The results showed that high stocking density significantly reduced the feed intake and body weight gain of broilers, while COMB improved the growth performance at high stocking density. High stocking density significantly reduced the liver metallothionein content, liver mitochondrial membrane potential and the activities of Na⁺K⁺-ATPase and Ca²⁺Mg²⁺-ATPase. In contrast, the liver metallothionein contents in the NAM, BA and COMB fed group were higher than those in the H group. COMB increased the activity of ATPase as well, but it failed to enhance the mitochondrial membrane potential. Stocking density also affected gut microbiota of broilers. The high-density group increased the relative abundance of Blautia. Supplementation of BA and NAM increased the abundance of Lactobacillus and Bifidobacteria, respectively. In conclusion, a combination of NAM and BA can improve the performance, antioxidant capacity, mitochondrial function and intestinal microbiota of broilers at high stocking density.

Probiotics and plant-derived compounds as eco-friendly agents to inhibit microbial toxins in poultry feed: a comprehensive review

Some of pathogenic bacteria and fungi have the ability to produce fetal toxins which may be the direct causes of cytotoxicity or cellular dysfunction in the colonization site. Biological and non-biological environmental factors, challenge and microbes influence the effect of toxins on these pathogens. Modern research mentions that many natural materials can reduce the production of toxins in pathogenic microbes. However, researches that explain the mechanical theories of their effects are meager. This review aimed to discuss the ameliorative potential role of plant-derived compounds and probiotics to reduce the toxin production of food-borne microbes either in poultry bodies or poultry feedstuff. Moreover, studies that highlight their own toxicological mechanisms have been discussed. Adding natural additives to feed has a clear positive effect on the enzymatic and microbiological appearance of the small intestine without any adverse effect on the liver. Studies in this respect were proposed to clarify the effects of these natural additives for feed. In conclusion, it could be suggested that the incorporation of probiotics, herbal extracts, and herbs in the poultry diets has some beneficial effects on productive performance, without a positive impact on economic efficiency. In addition, the use of these natural additives in feed has a useful impact on the microbiological appearance of the small intestine and do not have any adverse impacts on intestinal absorption or liver activity as evidenced by histological examination.