Impact of restricting feed and probiotic supplementation on growth performance, mortality and carcass traits of meat-type quails

Effect of dietary supplementation of macadamia oil on the growth, immune function, physio-biochemical components and thyroid activity of growing rabbits

The current research aimed to assess the effects of dietary macadamia oil (MO) on carcass traits, growth performance, physio-biochemical components, immune function, thyroid hormones and inflammation markers of growing rabbits. A total of 96 growing rabbits were randomly distributed into four treatments, with 24 rabbits in each group. The rabbits were fed a basal diet (control group) or a diet supplemented with MO at 0.5 (MO0.5), 1 (MO1.0) and 2 (MO2.0) mL/kg of diet for eight weeks. The daily body weight gain and feed conversion ratio showed a quadratic improvement with increasing levels of MO, and the optimal dose was 1.25 mL/kg of diet. Increasing levels of MO also had a quadratic effect on hepatic and renal functions. Dose-response curves revealed that the optimal doses of MO were 1.50, 1.75 and 1.25 mL/kg of diet for total bilirubin, gamma-glutamyl transferase, and creatinine respectively. A quadratic relationship was observed between the increased levels of MO and tumour necrosis factor-α (p = 0.038), interleukin-6 (p = 0.014) and immunoglobulins (p = 0.016 and IgM p = 0.026). Additionally, a linear relationship was observed between the increment in MO levels and both nitric oxide (p = 0.040) and interleukin-4 (p = 0.001). The activities of superoxide dismutase and glutathione peroxidase showed a linear increase with increasing dietary MO content, while xanthine oxidase showed a linear decrease. Total antioxidant capacity showed quadratic improvement (p = 0.035) with the dietary treatment, with the optimal dose observed at 1.25 mL/kg of diet. The inclusion of MO in the diet had a linear effect on the activity of thyroxine (p = 0.001). Therefore, supplementation of MO at a dose of 1 or 1.5 mL/kg of diet in growing rabbits' diets can improve growth and carcass traits, sustain thyroid function by supporting immunity, and reduce oxidative/inflammation pathways.

Impact of packaging atmosphere, oregano essential oil, and storage temperature on cold-adapted Salmonella Enteritidis and Salmonella Typhimurium on ready-to-eat smoked turkey

The hazard of diseases created by S. Enteritidis and S. Typhimurium is relatively high in turkey meat products. Combinations of preservation methods are utilized in many strategies, such as mild heat with decreased water activity, a changed atmosphere, refrigerated storage, and decreased heat treatment with some acidification. Within the domain of ready-to-eat food technology, a range of preservation methods are typically utilized to enhance shelf life, such as applying mild heat in tandem with reduced water activity, employing modified atmosphere packaging, utilizing refrigerated storage, and utilizing reduced heat treatment combined with acidification. This investigation aimed to determine how S. Enteritidis and S. Typhimurium grew when sliced ready-to-eat smoked turkey (RTE-SM) was stored at 0, 5, 10, and 15°C for various periods. The study also examined the effects of modified atmosphere packaging (MAP) (40% CO2 and 60% N2) and VP on these growth patterns. Total viable count (TVC), lactic acid bacteria (LAB), pH, and redox potential levels were determined. The control experiment on RTE-SM showed no Salmonella growth within 30 d of storage at any temperature. This indicated that the RTE-SM in use did not initially contain S. Typhimurium and S. Enteritidis. Results indicated that the storage of RTE-SM using a combination of VP, MAP, and MAPEO with storage at 0 and 5°C did not allow for the pathogen to grow throughout storage. In comparison, at 10 and 15°C after one day, which allowed for minor growth (0.17-0.5 log CFU/g)? In contrast, at 0 and 5°C, Salmonella survives until the end of storage (173 d). However, the combination of MAPEO with the same storage temperatures achieved the elimination of the pathogen in the meat after 80 d. The combination of both packaging systems with high temperatures (10 or 15°C) allowed for the multiplication and growth of the bacterium through the product's shelf life of more than 1 log CFU/g. Thus, a combination of MAP or MAPEO with low storage temperatures (0 or 5°C) inhibited the growth of the pathogen.

Does the marketing age impact growth performance, carcass traits, economic feasibility and hemato-biochemical properties of genetically-modified quails?

The meat of the quail is one of the most delicious types, as it is rich in minerals and vitamins, especially vitamin K, which is useful in treating nervous diseases. In the present investigation, based on their live body weight, 270 genetically-enhanced white quail chicks of mixed sex were randomly assigned to 3 groups, each with 90 chicks. The first group's birds were slaughtered at 28 d of age. The birds in the second group were slaughtered at 31 d, and the birds in the third group were slaughtered at 34 d. Results showed no significant difference between the various groups in the overall mortality rate index at the end of each fattening stage (P > 0.05). There were substantial variations (P ≤ 0.05) in the average live weight index between the first and both groups at each group's marketing age. With increasing marketing age, body weight increases. Quail chicks raised for 34 d received the lowest EPEF (28.90 points), followed by those raised for 31 d and 28 d, which received 33.37 and 37.32 points, respectively. The economic feasibility of the 3 groups, no significant differences in the profit index were observed at the age of 28 d. Compared to the marketing age of the other 2 groups, it was noted that the profit index decreased as the birds advanced in age. Delaying marketing to 31 d leads to a decrease in profit by 5.7%, and delaying marketing to 34 d reduces the profit index to 26.36% compared to marketing at 28 d. For blood hematology parameters, a significant increase in the studied indicators with the age of the birds was observed through the study of blood indicators. Still, it did not reach the significance level. It could be concluded that 28 d is the ideal marketing age for the enhanced white quails, as it yielded the highest economic return and the best performance.

Antimicrobial use and resistance in food animal production: food safety and associated concerns in Sub-Saharan Africa

The use of antimicrobials in food animal (FA) production is a common practice all over the world, with even greater usage and dependence in the developing world, including Sub-Saharan Africa (SSA). However, this practice which serves obvious economic benefits to producers has raised public health concerns over the last decades, thus driving the selection and dissemination of antimicrobial resistance and adversely impacting food safety and environmental health. This review presents the current and comprehensive antimicrobial usage practices in food animal production across SSA. We further highlighted the overall regional drivers as well as the public health, environmental, and economic impact of antimicrobial use in the production of food animals. Antimicrobial use is likely to increase with even exacerbated outcomes unless cost-effective, safe, and sustainable alternatives to antibiotics, especially probiotics, prebiotics, bacteriocins, antimicrobial peptides, bacteriophages, vaccines, etc. are urgently advocated for and used in food animal production in SSA. These, in addition to the implementation of strong legislation on antimicrobial use, and improved hygiene will help mitigate the public health concerns associated with antimicrobial use in food animals and improve the well-being and safety of food animals and their products.

Dietary Paenibacillus polymyxa AM20 as a new probiotic: Improving effects on IR broiler growth performance, hepatosomatic index, thyroid hormones, lipid profile, immune response, antioxidant parameters, and caecal microorganisms

The search for a natural antimicrobial agent is ongoing and critical because of the rise and rapid proliferation of antibiotic-resistant pathogenic bacteria. The current study aims to examine the effect of Paenibacillus polymyxa AM20 as an alternative antibiotic and feed additive on Indian river broiler performance, digestive enzymes, thyroid hormones, lipid profile, hepatosomatic index, immunological response, gut bacteria, and antioxidant parameters. The bacterial isolate AM20 was identified at the gene level by isolating DNA and using PCR to detect genes. Based on 16S rRNA gene sequence analysis, the bacterial isolate was identified as Paenibacillus polymyxa. One hundred twenty Indian river broilers (1-day old) were randomly divided into 4 groups of 10 chicks each, with 3 replicates. The control group was fed a basal diet only, while the other 3 were administered control diets supplemented with P. polymyxa at 3 concentrations: 0.5, 1, and 1.5 mg/kg. The findings revealed that all groups that received graded amounts of P. polymyxa increased all growth parameters throughout the study. P. polymyxa treatment at 1.5 mg/kg increased body gain by 9% compared to the control due to increased feed intake (P = 0.0001), growth rate (P = 0.0001), and decreased feed conversion ratio. Compared to the control group, P. polymyxa (1.5 mg/kg) enhanced kidney functions in chickens by reducing uric acid and creatinine levels (P = 0.0451). Compared to the control group, alanine aminotransferase and aspartate transaminase levels in the liver were significantly reduced at all P. polymyxa doses. Liver function values were highest for P. polymyxa at 1.5 mg/kg. Compared to the control group, those whose diets included P. polymyxa had significantly better blood cholesterol levels, high-density lipoprotein, low-density lipoprotein, immunological response, thyroid function, and gut microbiota. In general, broiler chickens' economic efficiency was improved by including P. polymyxa in their diet, which also improved their growth performance, carcass dressing, specific blood biochemical levels and enzymes, and the composition of the gut microbiota.

The Effects of Lactobacillus farciminis and Lactobacillus rhamnosus on Growth, Blood Biochemical, and Meat Quality Indicators of Specific Pathogen-Free Broiler Chickens

The aim of our study was to evaluate the effects of Lactobacillus farciminis and Lactobacillus rhamnosus on live weight gain, feed consumption indicators, and some metabolic blood biochemical and meat quality indicators of specific pathogen-free Ross 308 broiler chickens. We carried out the study in three trials and included a total of 780 unsexed Ross 308 chickens, which we randomly divided into two groups: the control group (Con, n = 390, basal diet) and the probiotic group (ProL, n = 390, basal diet + a powder consisting of L. farciminis and L. rhamnosus 4 g/10 kg of feed). We raised broilers until day 35. We determined the amount of feed consumed, the average daily weight gain, the feed conversion ratio, the average daily feed intake, and the cumulative feed intake once a week. We collected blood samples from 45 broilers from each group at the end of the study. In addition, we slaughtered 30 broilers from each group by cervical dislocation to obtain a breast muscle sample (without skin) to determine meat quality in these chickens (cholesterol and unsaturated, omega-3, omega-6, omega-9, and saturated fatty acids). Feeding a probiotic mixture containing L. farciminis and L. rhamnosus did not significantly affect the growth and feed intake indicators. Feeding these probiotics significantly lowered the blood serum cholesterol levels but did not provide the expected reduction in meat cholesterol levels. However, feeding a probiotic mixture increased the levels of polyunsaturated fatty acids (omega-3 and omega-6 fatty acids) in the breast meat and decreased saturated fatty acids. To better explain the effect of the combination of lactic acid bacteria (L. farciminis and L. rhamnosus) on the growth and development of broiler chickens in our study, histological and immunohistochemical examinations should be performed.

Pathogen inhibition and immunomodulation effects of probiotics and prebiotics against Salmonella spp. in chicken

This research investigated the effect of probiotics and prebiotics on the control of Salmonella spp. isolated from chicken. One hundred and eleven bacterial isolates were recovered from different chicken farms, and nine Salmonella isolates were detected with 8%. The serogroup analysis of nine Salmonella isolates showed three different groups identified as (4) S. enteridits, (3) S. typhimurium, and (2) untyped group. Identified Salmonella positive using PCR and genus-specific primer OMPCF (outer membrane protein reverse) with a target size of 204bp. The results of Salmonella enteridities with target size are also 304bp and target 401bp for Salmonella typhimurium.In the experiment, one hundred chicks were grouped into five groups (1, 2, 3,4&5) containing 20 broiler chicks. The broilers of groups (1, 2, 3, 4 & 5) were inoculated orally with a dose of 1 × 108 cfu nalidixic acid-resistant Salmonella enteridities. Group (1) is a control group, group (2) is not treated, group (3) is treated with B. Subtilis natto (1 ×108), group (4) is treated with Levoxyl, and group (5) is treated with panflor. The experiment results significantly increased the survival percentage against those challenged with a virulent strain of nalidixic acid probiotics and prebiotics significantly increases probiotics and prebiotics. The oral application significantly the survival percentage against challenges with a virulent strain of nalidixic acid-resistant Salmonella spp. Probiotics and prebiotics increase body weight gain and feed conversion rate (FCR). Effect of probiotic (Baccilus subtilis) on Salmonella spp. activity, the best result of B.subtilis is 1× 108 has been shown to reduce the growth of the microorganism under study (S. typimurium - S. enterditis).

Effects of probiotic supplements on growth performance and intestinal microbiota of partridge shank broiler chicks

Background

The benefits of probiotics being used in animals are well-documented via evidenced growth performance improvement and positive modulations of gut microbiota (GM). Thus, a combination of effective microorganisms (EM) has been frequently used in animal production, including broilers. However, there are only very limited reports of EM on the growth performance and the modulation in GM of partridge shank broiler chicks.

Methods

We attempted to evaluate the effects of a basal diet with the addition of an EM mixture on the growth performance and gut microbiome of the chicks. A total of 100 ten-day-old female partridge shank broiler chicks were randomly divided into two groups of 50 chicks each, of which, one group fed with EM supplementation in the basal diet (designated as EM-treated group), the other group just fed with a basal diet (referred as to non-EM treated group or control group). The body weight, daily feed intake, daily gain, feed conversion ratio and other growth parameters were observed and compared between EM-treated and non-EM-treated chicks, and the gut microbiota was profiled by 16S rRNA-based next generation sequencing (NGS).

Results

EM-treated chicks showed significantly increased performances in body weight (BW), average daily gain (ADG) and reduced feed conversion ratio (FCR). Histological observation indicated that dietary supplementation of EM significantly increased the villus heights (VH) and the ratio of villus height to crypt depth (VH/CD), while decreased the CD of jejunum, ilea, and ceca. The results of 16S rRNA-based gut microbiota analyses showed that Firmicutes accounted for the most of the relative abundance (63.24%∼92.63%), followed by Proteobacteria (0.62%∼23.94%), Bacteroidetes (0.80%∼7.85%), Actinobacteria (0.06%∼13.69%) and others in both EM-treated and non-EM-treated broiler chicks. The addition of EM could not alter the alpha diversity of gut microbiota. Compared with the non-EM-treated chicks, the abundances of bad bacteria in the phyla of Firmicutes, Euryarchaeota, and Ruminococcus were dramatically decreased in that of EM-treated chicks, while the abundances of good bacteria in the phyla of Actinobacteria and WPS-2 were significantly increased.

Conclusions

The supplementation of EM in feed could improve the growth performance and positively influence the morphological characteristics of the intestine, and ameliorate the community and structure of the intestinal microbiota of partridge shank broiler chicks.

Productive performance, fertility and hatchability, blood indices and gut microbial load in laying quails as affected by two types of probiotic bacteria

This study investigated two kinds of probiotic bacteria (Bacillus toyonensis, B1 and Bifidobacterium bifidum, B2) on laying Japanese quail’s performance, egg quality, fertility and hatchability, blood biochemical characteristics and microbiological parameters. A total of 270 mature quails (180 females and 90 males) were distributed into ten groups in a completely randomized design at eight weeks of age. The experimental groups were as follows: T1: basal diet only (control); T2-T5, basal diet plus 0.05, 0.075, 0.10 and 0.125% B1, respectively; T6: basal diet plus 0.10% B2; T7-T10: basal diet plus 0.05, 0.075, 0.10 and 0.125% B1 plus 0.05% B2, respectively. Results revealed that egg number (EN) and egg weight (EW) were gradually increased (P < 0.01) as the levels of both probiotic types increased. The feed conversion ratio (FCR) was significantly (P < 0.05) better within the total experimental period (8–20 weeks) due to B1 alone or/with B2 supplementation. Values of yolk percentage (Y%) were statistically (P < 0.01) higher only at 8–20 weeks of age and T10 recorded the highest value. By increasing the level of probiotics, fertility and hatchability percentages (F% and H%) were gradually increased (P < 0.01 and P < 0.05). Creatinine (CR) level was statistically reduced in birds fed T4 diet. Also, urea-N and aspartate aminotransferase (AST) levels were reduced in treated birds. The opposite was found regarding alkaline phosphatase (ALP). Conclusively, using B1 and B2 enhanced the productive performance, some egg quality traits, fertility and hatchability, digestive enzyme activities, and reduced the harmful bacteria in the gut of laying Japanese quail. Our findings could recommend to apply T4 (basal diet + 0.10 % B1), T6 (basal diet + 0.10% B2) and T9 (basal diet + 0.10% B1 + 0.05% B2) levels for the best results.

Bacillus amyloliquefaciens BLCC1-0238 Alone or in Combination with Mannan-Oligosaccharides Alleviates Subclinical Necrotic Enteritis in Broilers

Subclinical necrotic enteritis (SNE) is a severe intestinal disease in broilers which brings huge economic losses to poultry industry. Herein, the effects of Bacillus amyloliquefaciens BLCC1-0238 (B. amyloliquefaciens BLCC1-0238) alone or in combination with mannan-oligosaccharides (MOS) on the SNE challenge model in broilers were comprehensively explored. A total of 360 broilers were randomly divided into 4 groups, including an SNE infection control (IC), an antibiotic pretreatment control (AC), a B. amyloliquefaciens BLCC1-0238 pretreatment (BP), and a B. amyloliquefaciens BLCC1-0238 + MOS pretreatment (BMP). The results showed that compared with the IC, three pretreatment groups significantly improved the growth performance, lowered the overall mortality, and reduced intestinal mucosal lesions in broilers. Additionally, the expression levels of claudin-3 and peroxisome proliferator-activated receptor-gamma coactivator-1α in the BP and BMP groups and the levels of mucin-2 and mechanistic target of rapamycin in the BMP group were significantly upregulated compared with the IC. By contrast, the expression levels of interferon-γ, interleukin-10, and secretory immunoglobulin A in the BP and BMP groups were significantly downregulated. In conclusion, these findings show that B. amyloliquefaciens BLCC1-0238 in combination with MOS can exert synergetic effects by the interplay between them on improving growth performance and combating the SNE infection in broilers.

Role of Yeast and Yeast-Derived Products as Feed Additives in Broiler Nutrition

Antibiotic resistance is looming problem in broiler production globally and there has been an increasing interest to look for sustainable alternatives to antibiotics. Yeast and its derived products are recognized as potential feed additives because of their beneficial impacts on poultry. Particularly, yeast exhibited positive effects on the humoral immunity by increasing serum immunoglobulin (Ig) A levels. Moreover, yeast and its products showed immune adjuvant-like properties that helped the broilers chicken to develop faster and stronger innate immune response under pathogenic challenges. Use of yeast and its products as prebiotic/probiotic improves the gut architecture mainly by improving the gut development and gut microbiome, reduction in colonization of pathogens through competitive exclusion, binding of toxins and enhancing digestion and absorption of nutrients. These unique properties of yeast and yeast products enhance animal welfare and productivity; warrant them to be used as a promising feed additive. This article, therefore, provides insights into the functional role of yeast and its products in the broiler diets and highlights its importance as a commercially viable alternative of synthetic antibiotic growth promoters in the broiler feed industry.

Effect of Yeast-Fermented Citrus Pulp as a Protein Source on Nutrient Intake, Digestibility, Nitrogen Balance and In Situ Digestion Kinetics in Nili Ravi Buffalo Bulls

Simple Summary

A study was carried out to evaluate the effect of single cell protein (SCP) supplement as a protein source on nutrient intake, digestibility, nitrogen balance and in situ digestion kinetics in four Nili Ravi buffalo bulls. Four iso-caloric and iso-nitrogenous concentrates containing 3, 6, 9 and 12% of Saccharomyces cerevisiae-fermented citrus pulp were formulated and provided for 12 weeks. Chemical composition of fermented citrus pulp appeared as an excellent source of protein as no significant difference was observed on dry matter intake, digestibility of nutrients, SCP, ruminal pH and ammonia nitrogen. It is concluded that SCP could be used in the concentrate diet of ruminant up to 12%. Furthermore, the SCP has the potential of an alternative protein source in animal diet formulation.

Abstract

A study was carried out to evaluate the effect of single cell protein (SCP) supplement as a protein source on nutrient intake, digestibility, nitrogen balance and in situ digestion kinetics in four Nili Ravi buffalo bulls. Four iso-caloric and iso-nitrogenous concentrates containing 3, 6, 9 and 12% of Saccharomyces cerevisiae-fermented citrus pulp were formulated. All animals were fed a ration with a concentrate/forage ratio of 50:50. Diets were provided ad libitum twice a day as a total mixed ration in a 4 × 4 Latin Square Design. Each experimental period lasted 3 weeks while the overall study 12 weeks. The first 2 weeks of each experimental period were used as adaptation period while the third week as collection period. Chemical composition of fermented citrus pulp appeared as an excellent source of protein. No significant difference was observed on dry matter intake, digestibility of nutrients and SCP among all the treatments. Moreover, no significant effect was observed on ruminal pH and ammonia nitrogen at different times. Rate of disappearance and lag time of in situ dry matter digestion kinetics remained nonsignificant regardless of SCP percentage. Based on results of similar nutrients intake, nutrient digestibility, and ruminal parameters it is concluded that SCP could be used in the concentrate diet of ruminant up to 12%. Furthermore, the SCP has the potential of an alternative protein source in animal diet formulation.

Nutritional significance of amino acids, vitamins and minerals as nutraceuticals in poultry production and health - a comprehensive review

Nutraceuticals have gained immense importance in poultry science recently considering the nutritional and beneficial health effects of their constituents. Besides providing nutritional requirements to birds, nutraceuticals have beneficial pharmacological effects, for example, they help in establishing normal physiological health status, prevent diseases and thereby improve production performance. Nutraceuticals include amino acids, vitamins, minerals, enzymes, etc. which are important for preventing oxidative stress, regulating the immune response and maintaining normal physiological, biochemical and homeostatic mechanisms. Nutraceuticals help in supplying nutrients in balanced amounts for supporting the optimal growth performance in modern poultry flocks, and as a dietary supplement can reduce the use of antibiotics. The application of antibiotic growth enhancers in poultry leads to the propagation of antibiotic-resistant microbes and drug residues; therefore, they have been restricted in many countries. Thus, there is a demand for natural feed additives that lead to the same growth enhancement without affecting the health. Nutraceuticals substances have an essential role in the development of the animals' normal physiological functions and in protecting them against infectious diseases. In this review, the uses of amino acids, vitamins and minerals as well as their mode of action in growth promotion and elevation of immune system are discussed.

Dietary effect of probiotics and prebiotics on broiler performance, carcass, and immunity

This experiment was carried out to evaluate the effects of dietary addition of probiotics (Protexin) and prebiotics (active MOS, mannan oligosaccharides) on growth performance, carcasses, and antibody titer in broilers. A total number of 360-day-old Ross broiler chicks were randomly divided into 9 groups in a 3 × 3 factorial arrangement. Nine broiler starter (0-21 d) and finisher (21-35 d) diets were formulated by using 3 levels of probiotics (0, 1, and 2 g/kg of feed) and 3 levels of MOS (0, 1, and 1.5 g/kg of feed) and were randomly allotted to 9 groups. Feed intake was not affected by interaction of treatments during all phases (P > 0.05). Feed intake was improved due to the main effect of probiotic (P = 0.0001) or MOS (P = 0.005). No interaction (P > 0.05) was observed for weight gain in the starter, finisher, and overall phases. While, during the starter and finisher phases, weight gain was increased by probiotics (P = 0.028 or 0.04, respectively). Dietary supplementation of MOS improved weight gain (P = 0.01) and feed conversion ratio (FCR) (P = 0.03) during the overall period, but during starter and finisher periods, weight gain and FCR were not affected by prebiotics. Apart from dressing percentage, no interaction or individual effect of probiotics and prebiotics was observed for carcass, breast, thigh, heart, liver, and gizzard weight. Antibody titer for infectious bursal disease (IBD) was improved (P = 0.026) by the interaction effect between probiotics and prebiotics, when compared with the control group. Antibody titer against Newcastle disease (ND) was not affected by probiotics or prebiotics or their interactions (P > 0.05). It could be concluded that supplementation of prebiotics or probiotics can improve the growth performance of broilers. It may also be helpful in improving the antibody titer against IBD in broilers fed antibiotic-free diets.

Probiotics in poultry feed: A comprehensive review

The use of antibiotics to maintain animal well-being, promote growth and improve efficiency has been practised for more than 50 years. However, as early as the 1950s, researchers identified concern on the development of resistant bacteria for the antibiotics streptomycin and tetracycline used in turkeys and broilers respectively. These findings laid the groundwork for agricultural officials to impose stricter regulatory parameters on the use of antibiotics in poultry feeds. Probiotics are live micro-organisms included in the diet of animals as feed additives or supplements. Commonly known as a direct-fed microbial, probiotics provide beneficial properties to the host, primarily through action in the gastrointestinal tract (GIT) of the animal. Supplementation of probiotics in the diet can improve animal health and performance, through contributions to gut health and nutrient use. For instance, supplementation of probiotics has been demonstrated to benefit farm animals in immune modulation, structural modulation and increased cytokine production, which positively affect the intestinal mucosal lining against pathogens. Bacillus subtilis has been a popular bacterium used within the industry and was shown to improve intestinal villus height. Increasing the villus height and structure of the crypts in the GIT allows for the improvement of nutrient digestion and absorption. Tight junctions maintain important defences against pathogenic bacteria and cellular homeostasis. Heat stress can be a major environmental challenge in the poultry industry. Heat stress causes the bird to fluctuate its internal core temperature beyond their comfort zone. To overcome such challenges, poultry will attempt to balance its heat production and dissipation through behavioural and physiological adaptation mechanisms.

Study of the antibiotic residues in poultry meat in some of the EU countries and selection of the best compositions of lactic acid bacteria and essential oils against Salmonella enterica

In this study, the presence of antibiotics (ANB) residues was evaluated in poultry meat purchased from German and Lithuanian markets. In addition, the antimicrobial activity of 13 lactic acid bacteria (LAB) strains, 2 essential oils (EO) (Thymus vulgaris and Origanum vulgare L.), and their compositions were tested for the purpose of inhibiting antibiotic-resistant Salmonella spp. ANB residues were found in 3 out of the 20 analyzed poultry meat samples: sample no. 8 contained enrofloxacin (0.46 μg/kg), sample no. 14 contained both enrofloxacin and doxycycline (0.05 and 16.8 μg/kg, respectively), and sample no. 18 contained enrofloxacin (2.06 μg/kg). The maximum residue limits (MRLs) for the sum of enrofloxacin and ciprofloxacin and for doxycycline in the poultry muscle are 100 μg/kg. Finally, none of the tested poultry meat samples exceeded the suggested MRLs; however, the issue of ANB residues still requires monitoring of the poultry industry in Germany, Poland, and Lithuania, despite the currently established low ANB concentrations. These findings can be explained by the increased use of alternatives to ANB in the poultry industry. Our results showed that an effective alternative to ANB, which can help to reduce the occurrence of antibiotic-resistant salmonella, is a composition containing 1.0% of thyme EO and the following LAB strains: Lactobacillus plantrum LUHS122, Enteroccocus pseudoavium LUHS242, Lactobacillus casei LUHS210, Lactobacillus paracasei LUHS244, Lactobacillus plantarum LUHS135, Lactobacillus coryniformins LUHS71, and Lactobacillus uvarum LUHS245, which can be recommended for poultry industry as components of feed or for the treatment of surfaces, to control the contamination with Salmonella strains. However, it should be mentioned that most of the tested LAB strains were inhibited by thyme EO at the concentrations of 0.5 and 1.0%, except for LUHS122, LUHS210, and LUHS245. Finally, it can be noted that the agents responsible for the inhibitory effect on Salmonella are not the viable LAB strains but rather their metabolites, and further studies are needed to identify which metabolites are the most important.

Growth, carcass characteristics, meat quality, and microbial aspects of growing quail fed diets enriched with two different types of probiotics (Bacillus toyonensis and Bifidobacterium bifidum)

The present investigation aimed to explore the impact of dietary graded levels of 2 types of probiotic bacteria (Bacillus toyonensis [BT] and Bifidobacterium bifidum [BB]) on growth, carcass traits, meat quality, and bacteriology of growing Japanese quail reared under the cage system. One thousand three hundred sixty Japanese quail day-old chicks were randomly divided into 10 groups (8 replicates each). Birds were fed a basal diet (control, T1) and the basal diet plus 0.05, 0.075, 0.10, and 0.125% BT (T2, T3, T4, and T5, respectively), 0.10% BB (T6), and the same previous doses of BT plus 0.05% BB (T7, T8, T9, and T10, respectively). Results showed a significant (P < 0.001) increase in final BW and weight gain because of probiotic supplementation (except T2 for weight gain). Both feed intake and feed conversion ratio did not differ during the overall experimental period (1–42 D of age) except feed intake that was reduced in T2 and increased in T5 and T9 groups. All carcass traits studied were significantly (P < 0.01) affected by probiotics, and the combination between BT and BB in group T8 increased all studied parameters as compared with the other treatment groups. The quail meat color of redness a∗ and L∗ values, thiobarbituric content, cooking loss, proteolysis, and total coliform were decreased (P < 0.001) by probiotic treatment. In general, supplementing BT, BB, or their combination to the basal diet delayed the proliferation of pathogenic bacteria in the diet and intestine. Using BT and BB as feed supplements enhanced growth performance and meat quality of quails as well as diminished pathogenic bacteria proliferation in their diet and intestine. As per our results, we can recommend the application of T5 and T8 to T10 levels for the best performance, carcass traits, and meat quality of growing quails.

Effects of Dietary Chicory (Chicorium intybus L.) and Probiotic Blend as Natural Feed Additives on Performance Traits, Blood Biochemistry, and Gut Microbiota of Broiler Chickens

The experiment was designed to determine the effect of different levels of chicory (Chicorium intybus L.) powder and a probiotic blend (PrimaLac^®) on productive performance, blood biochemical parameters, and ileal microbiota in broiler chickens. A total of 225 one-day-old broilers (Ross 308) were used in a completely randomized design with five experimental diets as follows: 1—basal-diet without supplements (control-group); 2—basal-diet including probiotic blend; 3— basal-diet including 0.10% chicory; 4—basal-diet including 0.15% chicory; 5—basal-diet including 0.20% chicory. At 42 days of age, representative birds per replicate were randomly selected for blood samples and carcass measurements. Results showed that the body weight gain of broilers fed the probiotic blend or 0.10% chicory was significantly (P < 0.05) higher than those fed on the other treatments. The abdominal fat pad was significantly (P < 0.05) lower in birds fed diets including chicory compared with control or probiotic. Blood triglycerides and LDL levels were reduced (P < 0.05) and HDL increased (P < 0.05) when fed probiotic or chicory whereas no significant effect on the other serum parameters was found. Broiler ileal microflora from the control group had significantly (P < 0.05) higher count of E. coli and lower Lactobacillus than those from the other groups. From findings, it is possible to conclude that dietary chicory powder supported positively growth performance and improved gut microbiota in broiler chickens. However, more research is needed on this subject to better understand the mode of action of feed additives used.