Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Linking key husbandry factors to the intrinsic quality of broiler meat

Broiler farming is the fastest-growing animal production sector and broiler meat is the second most-consumed meat in the world. The intensification of broiler production often has a negative impact on the meat quality and carcass characteristics. Consumers, however, expect a quality product from animals reared extensively on farms providing good animal welfare, often intuitively associated with extensive farming practices. Therefore, this literature review investigates how the critical factors contributing to the degree of extensiveness of broiler production affect the quality of meat. We used the data from scientific articles published in the years 2012-2021 to analyze the effect of diet (n = 409), genetics (n = 86), enrichment (n = 25), and stocking density (n = 20) on meat quality and carcass characteristics. Minerals and microelements supplementation in the diet improved all the meat quality aspects: sensory, physical, and chemical in most studies. Minerals and enzymes in the diet had beneficial effects on carcass characteristics, unlike feed restriction and ingredient substitutions. The impact of outdoor access on meat quality and carcass characteristics was most frequently examined, in contrast to the use of perches or effects of litter quality. Overall, enrichment did not affect the meat's sensory or physical parameters, but outdoor access improved its lipid composition. Lower stocking density deteriorated intramuscular fat content, decreased tenderness and juiciness, yet lowered cooking and drip loss, and increased carcass and breast muscle yields. When it comes to genetics, in general, slow growing broiler strains have better meat quality parameters, especially regarding yellowness (b*), redness (a*), cooking and drip loss. Our review shows that the factors which contribute to extensiveness of broiler production systems and birds' welfare also affect meat quality and the carcass characteristics.

L-serine improves lipid profile, performance, carcass weight and intestinal parameters in feed restricted broiler chickens during the hot-dry season

The study evaluated effects of L-serine on lipid profile, performance, carcass weight and small intestinal parameters in heat-stressed broiler chickens subjected to feed restriction. Broiler chickens were divided into four groups, comprising 30 each. Group 1, feed restriction (FR); Group 2, feed restriction + L-serine (200 mg/kg) (FR + L-serine); Group 3, ad libitum (AL); Group 4, ad libitum + L-serine (200 mg/kg) (AL + L-serine). L-serine was administered orally from days 1 to 14, and feed restriction was performed on days 7-14. Serum harvested from blood samples on days 21, 28 and 35 was evaluated for lipid profile. Feed and water intake, live weight gain, organ and carcass weight were measured. At 35 days old, broiler chickens (n = 7) per group were sacrificed to evaluate small intestinal morphology. Temperature-humidity index in the pen (30.88 ± 0.81) was above thermoneutral zone, indicating that chickens were subjected to heat stress. Concentrations of low-density lipoprotein, total cholesterol and total triglycerides were lower (p < 0.05), while higher concentration of high-density lipoprotein was recorded in L-serine groups than in the controls. Feed intake and live weight gain on day 35 in L-serine groups were higher (p < 0.05) than in controls. In L-serine groups, liver, spleen, pancreas and heart weight were higher, but abdominal fat was lower than in FR and AL groups. Villus height:crypt height ratio and area of villus surface were highest in L-serine groups than any other group. In conclusion, L-serine decreased low-density lipoprotein, increased feed intake, live weight, organ and carcass weight, villus height:crypt height ratio and villus surface area.

Dietary strategies to alleviate high-stocking-density-induced stress in broiler chickens – a comprehensive review

Stocking broilers at a high density has been a strategy to optimize the area of the cage and hence increase the efficiency of broiler production. If the environmental (microclimate) conditions and rearing management are not properly managed, stocking broilers at a high density may, however, result in stressful conditions that are harmful for the production, health and welfare of broilers. To ameliorate these unfavorable effects of overcrowding stress, dietary interventions have been conducted. Probiotics, prebiotics, synbiotics, plant-derived products, vitamins, propolis, amino acids, fatty acids, etc. have been supplemented in diets to deal with the harmful impact of stress induced by a high stocking density of broilers. This review covers the detrimental effects of overcrowding-induced stress on broiler development and attempts to ameliorate those negative effects by dietary interventions.

Assessment of In Ovo Administration of Bifidobacterium bifidum and Bifidobacterium longum on Performance, Ileal Histomorphometry, Blood Hematological, and Biochemical Parameters of Broilers

Bifidobacterium is one of the most promising probiotics which was recently used as an alternative growth promoter in poultry. This trial was considered to evaluate the potential effects of in ovo administration of Bifidobacterium bifidum and Bifidobacterium longum on growth performance and biochemical parameters of broilers. Three hundred broiler breeder eggs were incubated and candled individually at day 17 of embryogenesis; then, eggs that had live embryos were randomly divided into six groups. The first and second groups were of intact (without injection) and vehicle-injected (sterile distilled water) control groups, respectively. Other groups were in ovo injected with 1 × 10⁹ and 1 × 10⁷ CFU B. bifidum, and 1 × 10⁹ and 1 × 10⁷ CFU B. longum, respectively. Hatchability was significantly (P < 0.001) affected by in ovo inoculation of bifidobacteria strains. Body weight gain and feed conversion ratio were significantly improved (P = 0.014 and 0.019, respectively) in all treatment groups. Protein fractions, aspartate aminotransferase, and alanine aminotransferase activities were not significantly altered by bifidobacteria strains in ovo injection. Regarding ileal histomorphometry parameters, a significant elevation in villus height and villus height/crypt depth ratio values were recorded while crypt depth was insignificantly affected by in ovo treatments. It could be concluded that the tested manual method of in-yolk sac injection at day 17 of incubation is more favorable in easier delivering of bifidobacteria strains which improve broiler growth performance and ileal development without any undesirable effects on blood indices and liver and renal functions.

Probiotics: an Antibiotic Replacement Strategy for Healthy Broilers and Productive Rearing

Pathogens develop resistance to antibiotics at a rate much faster than the discovery of new antimicrobial compounds. Reports of multidrug-resistant bacteria isolated from broilers, and the possibility that these strains may spread diseases amongst humans, prompted many European countries to ban the inclusion of antibiotics in feed. Probiotics added to broiler feed controlled a number of bacterial infections. A combination of Enterococcus faecium, Pediococcus acidilactici, Bacillus animalis, Lactobacillus salivarius and Lactobacillus reuteri decreased the colonisation of Campylobacter jejuni and Salmonella Enteritidis in the gastro-intestinal tract (GIT) of broilers, whereas Bacillus subtilis improved feed conversion, intestinal morphology, stimulated the immune system and inhibited the colonisation of Campylobacter jejuni, Escherichia coli and Salmonella Minnesota. Lactobacillus salivarius and Pediococcus parvulus improved weight gain, bone characteristics, intestinal morphology and immune response, and decreased the colonisation of S. Enteritidis. Lactobacillus crispatus, L. salivarius, Lactobacillus gallinarum, Lactobacillus johnsonii, Enterococcus faecalis and Bacillus amyloliquefaciens decreased the Salmonella count and led to an increase in lysozyme and T lymphocytes. Probiotics may also improve feed digestion through production of phytases, lipases, amylases and proteases or stimulate the GIT to secrete digestive enzymes. Some strains increase the nutritional value of feed by production of vitamins, exopolysaccharides and antioxidants. Bacteriocins, if produced, regulate pathogen numbers in the GIT and keep pro-inflammatory and anti-inflammatory reactions in balance.

Effect of graded levels of dietary Bacillus toyonensis and Bifidobacterium bifidum supplementation on growth, carcass traits and ileal histomorphometry and microbiota of growing quails

This experiment investigated the role of graded dietary levels of two probiotic strains (Bacillus toyonensis; BT and Bifidobacterium bifidum; BB) on the growth rate, carcass traits, physiological and histological aspects of growing Japanese quail. One thousand and three hundred sixty one-day-old un-sexed Japanese quail chicks were distributed randomly into ten groups. The 1st group served as a control and fed the basal diet without supplement while the 2nd, 3rd, 4th and 5th groups received the control diet supplemented with 0.05, 0.075, 0.10 and 0.125% BT, respectively. The 6th group fed the control diet plus 0.10% BB while the remaining groups (7th to 10th) received the basal diet incorporated with the previous levels of BT rich with 0.05% BB. Dietary supplementation of BT and/or BB increased body weight and gain; however, feed intake and feed conversion were not affected. Amylase activity was significantly elevated in 5th, 7th and 9th groups, while lipase activity was improved in all treatment groups except 3rd and 6th groups. Results obtained concluded that dietary supplementation of BT with or without BB is useful for performance, digestive enzyme activities, blood cholesterols, antioxidant status and ileal histomorphometry and microbiota of growing Japanese quail.

Nutritional manipulation to combat heat stress in poultry - A comprehensive review

Global warming and climate change adversely affect livestock and poultry production sectors under tropical and subtropical conditions. Heat stress is amongst the most significant stressors influencing poultry productivity in hot climate regions, causing substantial economic losses in poultry industry. These economic losses are speculated to increase in the coming years with the rise of global temperature. Moreover, modern poultry strains are more susceptible to high ambient temperature. Heat stress has negative effects on physiological response, growth performance and laying performance, which appeared in the form of reducing feed consumption, body weight gain, egg production, feed efficiency, meat quality, egg quality and immune response. Numerous practical procedures were used to ameliorate the negative impacts of increased temperature; among them the dietary manipulation, which gains a great concern in different regions around the world. These nutritional manipulations are feed additives (natural antioxidants, minerals, electrolytes, phytobiotics, probiotics, fat, and protein), feed restriction, feed form, drinking cold water and others. However, in the large scale of poultry industry, only a few of these strategies are commonly used. The current review article deliberates the different practical applications of useful nutritional manipulations to mitigate the heat load in poultry. The documented information will be useful to poultry producers to improve the general health status and productivity of heat-stressed birds via enhancing stress tolerance, oxidative status and immune response, and thereby provide recommendations to minimize production losses due to heat stress in particular under the growing global warming crisis.

Impact of multi-strain probiotic, citric acid, garlic powder or their combinations on performance, ileal histomorphometry, microbial enumeration and humoral immunity of broiler chickens

Heat stress, one of the critical obstacles to poultry sector in subtropical and tropical countries, reduces performance, immune response, and animal welfare. This study examined the effect of dietary inclusion of probiotic (PRO), citric acid (CIT), garlic powder (GAR) or their combinations on growth, blood constituents, ileal microflora and morphology and humoral immunity of broiler chickens subjected to cyclic heat stress. Four hundred ninety one-day-old Ross-308 broiler chicks were randomly allocated to 7 groups with 7 replicates of 10 birds each as follows: control (C) group received the basal diet without supplements, PRO, CIT and GAR groups supplemented with 0.5 g kg^-1 multi-strain probiotic mixture (MPM), citric acid and garlic powder, respectively. PRO-CIT and PRO-GAR groups treated with 0.5 g kg^-1 MPM, and 0.5 g kg^-1 citric acid and garlic powder, while CIT-GAR group fed diet with 0.5 g kg^-1 of citric acid and garlic powder. Results revealed that dietary supplements and their combinations improved (P < 0.001) growth performance and decreased abdominal fat of heat-stressed birds. Dietary supplements decreased (P < 0.01) serum concentrations of cholesterol, triglycerides and LDL, while HDL was elevated (P < 0.05). Feed additives reduced (P < 0.01) ileal enumeration of Escherichia coli and total coliform while Lactobacillus count was increased (P < 0.05) only in MPM-enriched groups. Supplementation of these natural products improved (P < 0.01) ileal architecture while humoral immune response was not significantly influenced except antibody titre against Newcastle disease virus which was increased (P < 0.05) in MPM-supplemented groups. Conclusively, addition of the dietary supplements and their combinations, particularly, probiotic and citric acid combination can improve productive performance, and intestinal flora and histomorphometry of broilers exposed to cyclic heat stress.

Use of Bacillus subtilis PB6 enriched with choline to improve growth performance, immune status, histological parameters and intestinal microbiota of broiler chickens

Context Probiotics used in poultry nutrition may promote the propagation of beneficial bacteria and limit the growth of pathogens, improving the body’s resistance to disease. Aims The aim of the study was to establish the dose and timing of administration of a probiotic preparation containing live cultures of Bacillus subtilis PB6 and choline that would have the most beneficial effect on histological parameters and microbiological status of the intestine, immune status, and growth performance of broiler chickens. Methods In total, 980 one-day-old Ross 308 male chickens, divided into seven groups of 140 (each group with seven replications of 20 individuals), were used in the experiment. The birds were reared until Day 42 of life. In the control group, birds received water without addition of the probiotic preparation. In three continuous treatments, birds received the probiotic preparation in their water at doses of 0.05, 0.1 or 0.25 g/L from Day 1 to Day 42 of rearing. In three periodic treatments, birds received the same doses of the probiotic preparation, but only during Days 1–7, 15–21 and 29–35 of rearing. Key results Addition of the probiotic preparation to the drinking water of broiler chickens increased the total number of aerobic bacteria as well as the length of the intestinal villi and the depth of the crypts. It also reduced the number of fungi and coliform bacteria. In addition, increases were noted in the lysozyme content, the phagocytic index, and the level of immunoglobulin A. Conclusions The probiotic preparation containing B. subtilis and choline administered continuously at a dose of 0.25 g/L in water throughout the rearing period had the most beneficial effect on the composition of the microbiome, and improved the mucous membrane structure of the intestine (increasing villus length and intestinal crypt depth), immunity, and growth performance of the broiler chickens. Implications The use of probiotics in poultry nutrition improves the health of animals and makes breeding more profitable. Administration of this probiotic improves disease resistance, jejunal histological parameters, and intestinal microflora of broiler chickens.

Impacts of Strain Variation on Response to Heat Stress and Boldo Extract Supplementation to Broiler Chickens

Simple Summary

One of the common approaches to alleviating heat-stress in poultry is nutritional manipulation using herbal extracts or their derivatives to maintain the health, welfare, and performance of birds. The present study investigated the protective effect of boldo leaf extract against the harmful effects of cyclic heat stress in two broiler strains (Arbor Acres; AA and Avian-48; AV). Administration of boldo in drinking water was able to restore growth and health traits to nearly normal values. Generally, AA chicks were better able to withstand heat stress and were also more likely to utilize boldo extract than AV chicks. The use of boldo leaf extract in poultry production can assist in mitigating the effect of heat stress, improving the antioxidant defense system, and increasing productivity and profitability.

Abstract

There is increasing interest in the use of natural antioxidant supplements in poultry diets as protection against the adverse effects of heat stress. The potential protective effect of boldo (Peumus boldus molina) leaf extract, which have antioxidant activity, were investigated against the harmful effects of heat stress in two broiler strains. Arbor Acres (AA) and Avian-48 (AV) chicks were divided into thermoneutral (TN) and heat stress (HS) groups and treated with 1 g boldo leaf extract/4 L drinking water during the heat stress period. HS reduced growth performance in both strains. The phagocytic index, phagocytic activity, and eosinophil and lymphocytes counts were significantly elevated in TN and HS AV birds but not altered in AA birds. Boldo extract treatment partially eliminated the previous negative impacts of heat stress. AA chicks were better able to withstand HS than AV chicks. Serum concentrations of total lipids and cholesterol were reduced in HS birds of both strains. Malondialdehyde, superoxide dismutase, and glutathione peroxidase levels were elevated but restored with the administration of boldo leaf extract in HS birds of both strains. Economic parameters were negatively affected by HS but restored to values close to those of the control group in boldo-treated HS birds. In conclusion, the administration of boldo leaf extract in drinking water was effective in neutralizing the harmful effects of heat stress on growth performance, blood indices, and economic parameters and improved the antioxidant defense system in heat-stressed birds.

Effect of dietary supplementation of Bacillus subtilis spores on growth performance, oxidative status, and digestive enzyme activities in Japanese quail birds

The present trial investigated the feeding effect of B. subtilis spores on growth performance, blood metabolites, antioxidative status, and digestive enzyme activities in growing quails. A total of 750 1-day-old Japanese quail chicks were randomly allotted equally into five experimental groups: control (BS0) fed a maize-soybean basal diet with no additives, the others were supplemented with: B. subtilis spores with the levels of 1 × 10³ (BS3), 1 × 10⁵ (BS5), 1 × 10⁷ (BS7), and 1 × 10⁹ (BS9)/kg diet. Quails fed on B. subtilis diets exhibited linearly increasing live body weight and body weight gain and decreased feed-to-gain ratio compared with the control group. Daily feed intake was not significantly altered. Increasing levels of B. subtilis led to a linear increase in serum total protein and albumin levels, and a linear decrease in concentrations of glucose, creatinine, urea-N, aspartate aminotransferase, and alanine aminotransferase. Hypolipidemic impact of feeding B. subtilis spores was greatly observed and enhanced by increasing its dietary inclusion level. Triiodothyronine and thyroxine activities were significantly elevated in treated groups. Glutathione content and catalase activities were linearly increased in groups BS7, BS9, and BS5, while lipid peroxidation was decreased in all treatment groups. Duodenal proteolytic, lipolytic, and amylolytic activities as well as nutrient digestibility were linearly increased in treated groups. In conclusion, dietary supplementation of B. subtilis spores almost at all studied levels was able to promote the antioxidative status and digestive enzymes activities, while only the high concentrations (BS7 and BS9) could improve the nutrient digestion and growth performance of growing Japanese quail.