Effects of Phage Cocktail, Probiotics, and Their Combination on Growth Performance and Gut Microbiota of Broiler Chickens

Phages, which are often used therapeutically, have begun to receive interest as alternatives to antibiotic growth promoters (AGPs) for enhancing chicken growth. Another option that has been extensively studied as a growth promoter in chickens is probiotics. To the best of our knowledge, there is currently no study available on the use of phages and probiotics in combination as potential feed additives for broiler chickens. Therefore, this study demonstrated the effects of a phage cocktail, probiotics, and their combination on the growth performance and gut microbiota of broiler chickens. A total of 288 one-day-old male Cobb 500 broilers were randomly allotted to one of six treatments in a completely randomised design. The treatments were (i) C (basal diet (BD) only), (ii) 1ϕ (BD + 0.1% phage cocktail), (iii) 2ϕ (BD + 0.2% phage cocktail), (iv) P (BD + 0.1% probiotic), (v) 1ϕP (BD + 0.1% phage cocktail + 0.1% probiotic), and (vi) 2ϕP (BD + 0.2% phage cocktail + 0.1% probiotic). The 1ϕP treatment had significantly (p < 0.05) better BW (35 days), BWG (22-35 days, 1-35 days), and FCR (1-21 days, 22-35 days, 1-35 days) compared to C. Unique gut microbiota diversity was also found between the ϕP (1ϕP and 2ϕP) and non-ϕP groups (C, 1ϕ, 2ϕ, and P) in ilea, particularly in the 35-day-old chickens. Microorganisms associated with short-chain fatty acid (SCFA) producers were significantly (p < 0.05) more present in the ϕP group than in the non-ϕP group. The predicted genes related to carbohydrate and amino acid metabolism were significantly upregulated in ϕP groups compared to non-ϕP groups. These genes were involved in the digestion and absorption of nutrients, as well as the production of energy. Our findings showed that the 1ϕP treatment could be a potential alternative to AGPs for poultry, as growth performance was enhanced, and gut microbiota was positively modulated.

Effects of early feeding of enzymatically treated yeast on growth performance, organ weights, intestinal histomorphology and ceca microbial metabolites in broiler chickens subjected to Eimeria challenge

The study evaluated effects of early feeding of enzymatically treated yeast on growth performance and selected physiological responses in broiler chickens. A total of 480-day-old (male) Ross × Ross 708 broiler chicks were placed in 24 floor pens (20 birds per pen) and allocated to 2 diets (control vs. yeast) in a completely randomized block design (n = 12). Diets were formulated for a 5-phase feeding program: Pre-starter; d 0 to 6 Starter; d 7 to 15, Grower: d 16 to 28, Finisher 1; d 28 to 42 and Finisher 2; d 43 to 56. The yeast was applied in pre-starter and starter diets at 0.6 and 0.2%, respectively. Birds received a common diet from d 16 to 56. Feed intake (FI) and body weight (BW) were recorded by phase for calculation of BW gain (BWG) and FCR. On d 10, all birds received an oral dose of 25,000 E. acervullina and 5,000 E. maxima sporulated oocysts in 1 mL of sterile saline. On d 15 post-hatch, one bird per pen was sacrificed for organ weights (gizzard, small intestine, ceca, liver, spleen, liver, and bursa), jejunal tissues for histomorphology and ceca digesta for microbial activity. On d 56, one bird per pen was sacrificed for organs and breast weight. In pre-starter phase, yeast fed birds showed improved (P < 0.05) BWG and FCR than control fed birds. Combining pre-starter and starter phases, the FCR of yeast fed birds showed improved FCR (1.115 vs. 1.135; P < 0.05) than control. The overall BWG (d 0–56) was 3.920 and 3.962 kg/ bird and corresponding values for FCR were, 1.808 and 1.755, for the control and yeast, respectively. Diets had no (P > 0.05) effects on physiological responses evaluated on necropsied birds except that yeast birds had (P < 0.05) lighter bursa than control birds on d 15. The current data indicated that yeast could support growth in early life of broiler chickens, but these effects were not sustained after the transitioning birds to common grower and finisher diets.

Growth Performance, Serum Biochemical Indices, Duodenal Histomorphology, and Cecal Microbiota of Broiler Chickens Fed on Diets Supplemented with Cinnamon Bark Powder at Prestarter and Starter Phases

Ross 308 broiler chicks (n = 240) aged 1 day were assigned to five groups for eight replicates (six chicks for each) (3♂ and 3♀). Basal dietary groups were supplemented by 2000, 4000, and 6000 mg/kg cinnamon (CN) for 21 days. Basal diet alone was used as a negative control, and basal antibiotic diet (Colimox) was used as a positive control. At 10, 14, and 21 days of age, chicks that received 2000 mg CN and Colimox had a higher body weight, resulting in an increase in body weight gain. CN also resulted in the maximum improvement in the feed conversion ratio and feed efficiency over 1-21 days at the level of 2000 mg/kg. At days 10, the maximum relative breast weight was 2000 mg/kg of CN. Mean serum albumin concentrations, duodenal villus height, and goblet cell density increased (p < 0.05) by 2000 mg/kg of CN, and mean serum globulin and total protein concentrations and crypt depth increased (p < 0.05) by 6000 mg/kg of CN compared with control. Increased cecal Escherichia coli number was CN dose-dependent. In conclusion, dietary inclusion of 2000 mg/kg CN can be applied as an alternative to in-feed antibiotics for broiler starter diet.

Assessment of a Potential Role of Dickeya dadantii DSM 18020 as a Pectinase Producer for Utilization in Poultry Diets Based on in silico Analyses

Currently, the poultry industry has been faced with consumer pressure to utilize only vegetable feedstuffs in poultry diets, eliminate antibiotics from poultry production, and rear poultry in free range systems. To maintain current production standards, the industry must determine ways to enhance nutrient uptake and utilization further. One possible solution is the supplementation of pectinase, an enzyme that degrades pectin within the cell walls of plants, in poultry diets. Therefore, the objective of the current study was to determine the potential role of a pectinase producer, Dickeya dadantii DSM 18020, as a commercially utilized pectinase producer in poultry diets against other known pectinase producers, in silico. In the current study, whole genomes of Dickeya dadantii DSM 18020 (Dd18020), D. dadantii 3937 (Dd3937), D. solani IPO 2222 (Ds2222), Bacillus halodurans C-125 (BhC125), and B. subtilis subsp. subtilis str. 168 (Bs168) were compared using bioinformatic approaches to compare the chromosomal genome size, GC content, protein coding genes (CDS), total genes, average protein length (a.a.) and determine the predicted metabolic pathways, predicted pectin degrading enzymes, and pectin-degradation pathways across pectinase producers. Due to insufficient information surrounding the genome of Dd18020 (lack of annotation), the genome of Dd3937, a 99% identical genome to Dd18020, was utilized to compare pectinase-associated enzymes and pathways. The results from the current study demonstrated that Dd3937 possessed the most significant proportion of pathways presented and the highest number of pathways related to degradation, assimilation, and utilization of pectin. Also, Dd18020 exhibited a high number of pectinase-related enzymes. Both Dd3937 and Dd2222 shared the pectin degradation I pathway via the EC 3.1.1.11, EC 3.2.1.82, and EC 4.2.2.- enzymes, but did not share this pathway with either Bacillus species. In conclusion, Dd18020 demonstrated the genetic potential to produce multiple pectinase enzymes that could be beneficial to the degradation of pectin in poultry diets. However, for Dd18020 to become a commercially viable enzyme producer for the poultry industry, further research quantifying the pectinase production in vitro and determining the stability of the produced pectinases during feed manufacturing are necessary.

Characterizing Woody Breast Myopathy in a Meat Broiler Line by Heat Production, Microbiota, and Plasma Metabolites

Selection for quantitative traits in meat broilers such as breast yield and growth rate exert physiological pressure leading to ante mortem histological and biochemical alterations in muscle tissues. The poultry industry has recently witnessed a myopathy condition affecting Pectoralis major (breast muscle) of broilers, called woody breast (WB), an etiology still unclear to scientific community. A study was conducted to characterize the WB myopathy in a meat broiler line at its finishing phase (d 41) in terms of heat production (HP), microbiota and plasma metabolites. Two treatment groups were studied-WB affected (myopathy) and normal (non-myopathy) broiler; n = 20 in each group. Indirect calorimetry was utilized for HP measurement. Furthermore, body composition (BC) analysis was also performed using dual-energy x-ray absorptiometry (DEXA). Microbiota in ileal digesta was studied with PCR amplified 16s rRNA gene. LC-MS targeted metabolomics was performed to understand differential expression of plasma metabolites. Results showed that there was difference in fasting HP (P < 0.05) between these two treatment groups, with non-myopathy broiler producing more heat which was indicative of higher body protein content validated by higher protein: fat ratio by BC results. Less protein content in myopathy bird could be due to probable higher mixed muscle degradation occurring in lean tissue as marked by elevated 3-methylhistidine expression in plasma. Microbiota results showed unclassified Lactobacillus as predominant genus with higher abundance occurring in myopathy group; whereas at species level, L. acidipiscis was predominant bacteria for non-myopathy broiler. Differentially significant metabolites (P < 0.05) identified from plasma metabolome between these two treatment groups were homocysteine, cyclic GMP, trimethylamine N-oxide (TMAO), tyramine, carnitine, and acetylcarnitine, which were all associated to cardiovascular system. The findings suggest that more research in meat broilers could be opted toward delivering reduced vascularity issues to alleviate this myopathy condition.

Effects of pre-starter and starter diets varying in amino acid density given to broiler chickens that received coccidiosis vaccination at hatch1

An experiment was conducted to evaluate broilers vaccinated against coccidiosis fed combinations of pre-starter and starter diets varying in digestible amino acid (dAA) density from 1 to 19 d of age on subsequent growth performance and meat yield. A total of 1,800 Yield Plus Ross × Ross 708 male broilers were allocated to 60 floor pens and assigned to 1 of the 6 treatments. Four pre-starter diets varying in dAA density [1.15% dLys, 1.25% dLys, 1.35% dLys, and Positive Control (1.15% dLys + Diclazuril)] were fed until 9 d of age. Then, 3 starter diets varying in dAA density [1.15% dLys, 1.25% dLys, and PC (1.15% dLys + Diclazuril)] were given from 10 to 19 d of age. All diets were formulated to similar dAA ratios to dLys; hence, resulting in increasing amino acid (AA) density among the dietary treatments. Birds were given common grower and finisher diets for the remainder of the experiment. At 19, 27, and 40 d of age, broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had increased BW gain (P ≤ 0.006) compared with broilers fed the 1.15% dLys density diets. Broilers that received the 1.15% dLys density pre-starter diet had a lower cumulative BW gain (P = 0.007) than those fed the 1.35% and 1.25% dLys density pre-starter diets. Broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had the heaviest (P ≤ 0.008) total breast weights. Increasing the pre-starter dAA density enhanced (P ≤ 0.03) total breast weight by 28 g (1.25% dLys density) and 51 g (1.35% dLys density). Results from this study indicated that increasing dAA density from 1 to 19 d of age enabled a 1 to 19 d dAA intake increase of 4.8 g, which enhanced cumulative growth and meat yield of broilers vaccinated against coccidiosis.

Early Nutrition Programming (in ovo and Post-hatch Feeding) as a Strategy to Modulate Gut Health of Poultry

Healthy gastrointestinal tract (GIT) is crucial for optimum performance, better feed efficiency, and overall health of poultry. In the past, antibiotic growth promoters (AGP) were commonly used to modulate the gut health of animals. However, considering the public health concern, the use of AGP in animal feeding is banned or regulated in several jurisdictions around the world. This necessitates the need for alternative nutritional strategies to produce healthy poultry. For that, several alternatives to AGP have been attempted with some success. However, effective modulation of the gut health parameters depends on the methods and timing of the compound being available to host animals. Routinely, the alternatives to AGP and other nutrients are provided in feed or water to poultry. However, the GIT of the newly hatched poultry is functionally immature, despite going through significant morphological, cellular, and molecular changes toward the end of incubation. Thus, early growth and development of GIT are of critical importance to enhance nutrients utilization and optimize the growth of poultry. Early nutrition programming using both in ovo and post-hatch feeding has been used as a means to modulate the early growth and development of GIT and found to be an effective strategy but with inconsistent results. This review summarizes the information on in ovo and post-hatch-feeding of different nutrients and feeds additives and their effects on gut development, histomorphology, microbiology, and immunology. Furthermore, this review will provide insight on the future of early nutrition programming as a strategy to enhance gut health, thereby improving overall health and production so that the poultry industry can benefit from this technique.

Composition of more specialised pre-starter and starter diets for young broiler chickens: a review

The broiler industry has experienced remarkable improvements in productivity owing to high priority placed on genetic programming, nutrition and management practices. Nutrition of the meat chicken is driven by the need to satisfy the constantly increasing genetic potential, resulting in the shortening of the rearing time required to get the bird to market weight. The concept of feeding broilers a more specialised pre-starter diet for the first 10–14 days of age is gaining interest, as this now accounts for more than 20% of the time for grow-out. Specialised diets may be formulated to be highly digestible or aim to provide specific nutrients at a higher level to meet nutritional requirements of the bird. The effectiveness of specifically formulated pre-starter or starter diets depends on potential carryover effect to increase the bird performance up to the market age. There is evidence that some nutrient requirements of birds, digestible amino acids in particular, in the first 10 days of life may be higher than the current industry recommendation. Among cereals, rice with its lower non-starch polysaccharide content may be a better cereal for pre-starter diets than are corn or wheat. Inclusion of fibrous ingredients in low-fibre diets of young broilers may also stimulate gut development and enhance nutrient utilisation, leading to improved bird performance. There are inconsistencies in responses to various feed additives tested specifically for pre-starter diets of broilers. Finally, with an increasing demand for removal of antibiotic growth promoters from all broiler feeds, focus on formulations to ensure sustainable growth at start will gain importance.