Essential oils as growth-promoting additives on performance, nutrient digestibility, cecal microbes, and serum metabolites of broiler chickens: a meta-analysis

Transcriptomic and metabolomic-based revelation of the effect of fresh corn extract on meat quality of Jingyuan chicken

To investigate the effect of fresh corn extract (FCE) on chicken meat quality, 135-day-old Jingyuan chicken hens were fed diets containing different doses of FCE (CON, 0.3% FCE, 0.6% FCE and 0.9% FCE) until 180 day-old in this study. Meat performance measurements showed that the 0.6% FCE group of Jingyuan chickens had higher intramuscular fat (IMF), pressing loss (PL), amino acid and fatty acid contents (P < 0.05). Their breasts were collected for transcriptomic and metabolomic analyses (n=8), and 210 Differentially expressed genes (DEGs) and 29 Differentially expressed genes (DEMs) were obtained. Gene Ontology (GO) analyses of DEGs indicate multiple entries involved in IMF synthesis such as skeletal system development and cellular response to amino acid stimulation. Kyoto Encyclopedia of Genes and Genomes (GSEA-KEGG) analysis identified sphingolipid_metabolism and multiple genes affecting IMF deposition including SPHK1, CERS1, CERS6, GLB1L, SGMS2, UGT8, and UGCG. KEGG and metabolite correlation analyses of DEMs identified Aspartate, PI 38:5; PI(18:1/20:4), PI 36:3; PI(18:1/18:2), PI 36:2; PI(18:0/18:2), and PI 34:1; PI(16:0/18:1) as the likely major influences on IMF deposition in the DEMs. Correlation analysis revealed that shear force (SF) was significantly and positively correlated with Aspartate and CERS6; PL was significantly and positively correlated with SPHK1 and UGCG (P < 0.05). IMF was significantly and positively correlated with PI 34:1; PI (16:0/18:1), SPHK1 and UGCG; and flesh colour yellowness b* was significantly and positively correlated with SGMS2 (P < 0.05). The above results indicate that feeding a basal diet containing 0.6% FCE can improve the meat quality of Jingyuan chicken, which provides a theoretical basis for improving the meat quality of Jingyuan chicken.

Beneficial effects of ε-polylysine on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet

This study was conducted to investigate the effects of dietary ε-polylysine supplementation on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet. A total of 960 one-day-old yellow-feathered broilers were randomly allocated into six groups with eight replicates and 20 birds per replicate. Birds in the six groups were fed a lysine-deficient basal diet (-0.20 % lysine, NC) or basal diets supplemented with 0.20 % L-lysine hydrochloride (normal lysine level, PC) or varying levels (0.10 %, 0.20 %, 0.30 %, or 0.40 %) of ε-polylysine hydrochloride for 10 weeks. Results showed that compared with the NC group, dietary supplementation with 0.10 % and 0.20 % of ε-polylysine improved growth performance, meat quality and intestinal morphology, evidenced by increased average daily gain, decreased feed-to-gain ratio, increased water holding capacity of breast muscle, and increased jejunal and ileal villus height in ε-polylysine-treated broilers (P < 0.05). In addition, 0.10 % and 0.20 % of ε-polylysine supplementation improved serum nitrogen metabolism, immune and antioxidant capacity to varying degrees. No significant diffrences in growth performance, meat quality, or intestinal morphology were observed among PC and ε-polylysine-supplemented groups (P > 0.05). Interestingly, compared with the PC group, dietary 0.10 % of ε-polylysine positively altered the microbiota composition of broilers, evidenced by the increased the relative abundance of beneficial bacteria (e.g., Faecalibacterium and Phascolarctobacterium) and decreased the abundance of harmful bacteria (e.g., Lachnoclostridium and Peptococcus). In conclusion, diets supplemented with ε-polylysine have beneficial effects on growth performance, meat quality, and gut health of broilers via replenishing lysine or favorably altering immune and antioxidant capacity and gut microbiota. The recommended supplemental amount of ε-polylysine in lysine-deficient diets (L-lysine content in the starter and growing diet is 0.95 % and 0.80 % of the basal diet, respectively) is 0.10 %-0.20 %.

Effects of combined use of compound acidifiers and plant essential oils in feed on the reproductive performance and physiological status of Xianjv chickens

This study investigates the effects of combined compound acidifiers and plant essential oils on the production performance, egg quality, and health parameters of Xianjv chickens. A total of 240 healthy 34-week-old Xianjv chickens were randomly divided into 5 groups and given 5 different feed additives: a control group with a basal diet, and four experimental groups with varying doses of compound acidifiers (CA) and essential oils (EO). The results revealed that the addition of compound acidifiers and essential oils did not significantly affect average daily feed intake, egg production rate, or feed-to-egg ratio. However, supplementation with CA and EO significantly improved eggshell strength, albumen height, and Haugh unit, enhancing overall egg quality. Additionally, the combination of these additives enhanced serum antioxidant capacity by increasing levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), while reducing malondialdehyde (MDA) levels. It also lowered inflammatory cytokines such as interleukin-2 (IL-2) and interleukin-6 (IL-6) and improved intestinal health by enhancing digestive enzyme activities, including trypsin and lipase, in the duodenum and jejunum. The study concludes that the combined use of compound acidifiers and plant essential oils offers a promising alternative to antibiotics in poultry feed, improving egg quality and supporting better health status in Xianjv chickens. Nevertheless, careful optimization of the dosages and combinations is necessary to maximize their benefits without adversely affecting the birds' physiological balance.

Beneficial effects of Lactobacillus plantarum on growth performance, immune status, antioxidant function and intestinal microbiota in broilers

Lactobacillus plantarum (L. plantarum) has been globally regarded as antibiotic alternative in animal farming in the past few years. However, the potential function of L. plantarum in broilers has not been systemically explored. In this study, a total of 560 one-day-old yellow-feathered broilers were randomly divided into 3 groups, fed with basal diet and drank with L. plantarum HJZW08 (LP) at the concentration of 0 (CON), 1000 × 10^5 (LP1000), and 2000 × 10^5 CFU/L (LP2000) for 70 d. Results showed that the body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), immunoglobulin A (IgA), IgY, and anti-inflammatory interleukin 10 (IL-10) were markedly improved (P < 0.05), while the levels of pro-inflammatory IL-2, IL-1β, IL-6, and tumor necrosis factor-α (TNF-α) in serum were decreased (P < 0.05) in the LP2000 group comparing with the CON group. Besides, LP treatment groups prominently increased the levels and activities of antioxidant enzymes and decreased the content of malondialdehyde (MDA). Additionally, the levels of isobutyric acid in the LP1000 and LP2000 groups and isovaleric acid in the LP2000 group were significantly improved. More importantly, the α-diversity and microbial structure of intestinal microbiota were pronounced altered by LP supplementation. The results showed that only the relative abundance of Actinobacteriota was significantly increased in the LP2000 group, while 6 kinds of bacteria on genus level were significantly changed. For further validation, linear discriminant analysis with effect size (LEfSe) plots revealed that 8 amplicon sequence variants (ASVs) were predominant in the CON group, while Bacteroides and other beneficial species such as Lactimicrobium massiliense (ASV4 and ASV36), Intestinimonas butyriciproducens (ASV71), and Barnesiella viscericola (ASV152 and ASV571) were enriched in the LP groups. Taken together, dietary supplementation with LP obviously enhanced the immune status, antioxidant capacity, and stabilized the cecal microbiota and SCFAs, contributing to the improvement of growth performance of broilers. Our study laid good foundation for the application of probiotic Lactobacillus in animal industry in the future.

Nano-protected form of rosemary essential oil has a positive influence on blood biochemistry parameters, haematological indices, immune-antioxidant status, intestinal microbiota and histomorphology of meat-type chickens

This study aimed to investigate the potential of free and nanoprotected rosemary essential oil (REO) as an antibiotic alternative in blood biochemistry, hematology, immune-antioxidant status, intestinal microbiology, and histomorphology of broilers. A total of 420 1-wk-old broiler chicks (Cobb) were randomly allotted into 7 treatments, each having 4 replicates of 15 chicks. The first group served as control received basal diet, while the second group was fed a basal diet plus 100 mg/kg enramycin and third group basal diet plus 150 mg/kg chitosan nanoparticles (CNPs). The fourth and fifth groups received diets supplemented with 100 mg and 200 mg free REO (F-REO)/kg diet. The sixth and seventh groups were supplemented with 100 mg and 200 mg nanoprotected REO (N-REO)/kg diet. Results revealed that supplementing nanoprotected REO significantly (P < 0.05) decreased the levels of blood cholesterol and low-density lipoproteins (LDL) compared to control and enramycin groups. The kidney and liver function parameters were not altered by adding free or nanoprotected REO to the diet. Both levels of nanoprotected REO significantly (P < 0.05) reduced heterophil: lymphocyte (H: L) ratio compared to all other groups. Birds receiving nanoprotected REO at 200 mg/kg diet had significantly (P ˂ 0.05) raised serum levels of immunoglobulin G (IgG) and immunoglobulin M (IgM) compared to control and other birds. Anti-SRBC titre and cell-mediated immunity improved significantly (P < 0.05) in nanoprotected REO groups. Supplementation of nanoprotected REO resulted in significantly (P < 0.05) higher values for superoxide dismutase (SOD), glutathione (GSH) and total antioxidant status (TAS). The caecal microbiota was improved in broiler birds fed diets supplemented with nanoprotected REO. The 200 mg nanoprotected REO/kg diet supplementation resulted in significantly (P < 0.05) better villus height (VH) and villus height: crypt depth (VH: CD) ratio in all the segments of the small intestine. In conclusion, feeding REO in nanoprotected form in a 200 mg/kg diet could be used as an antibiotic substitute to improve broiler chicken's lipid profile, immune-antioxidant status, and intestinal health.

Leptin, adiponectin, biochemicals, metabolic hormones and performance characteristics of broiler administered with spices essential oil

A study was conducted to evaluate adipokines, metabolic hormones and serum biochemicals of broiler chicken administered with essential oils (EO) of turmeric, ginger, cinnamon and garlic. EO of the four spices were extracted by steam distillation using standard procedures. The EO were administered to 200 one- day-old unsexed broiler birds randomly allotted to five treatment groups (each of the four spices EO plus a control group) replicated 10 times in a completely randomized design. The spices EO were added to water consumed by the birds at 30 ml/L and standard diets were fed in a 42-day feed trial to determine weight changes and feed consumption. At the end of the trial, blood samples were collected, serum obtained and were assayed for metabolic and biochemical indicators. Results obtained indicates that the weight gain trends shows that birds on cinnamon EO and garlic EO were significantly (p < 0.05) higher than those on turmeric EO. Abdominal fat of birds on EO were significantly (p < 0.05) lesser than birds on control. Cholesterol of birds on EOs-based treatments were significantly (p < 0.05) lesser than birds on control. Triiodothyronine of birds were not significantly influenced by EOs. Insulin of birds on EOs were statistically (p < 0.05) reduced compared with those on control. Consumption of cinnamon EO significantly (p < 0.05) increased adiponectin of birds compared with garlic EO. Intake of garlic EO significantly (p < 0.05) enhance leptin of birds compared with cinnamon EO. This study suggests that cinnamon and garlic EO are potent oral phytogenic supplements to promote growth and lean yield in broiler chicken.

Oregano essential oil and Bacillus subtilis role in enhancing broiler's growth, stress indicators, intestinal integrity, and gene expression under high stocking density

This study investigates the role of dietary Bacillus subtilis and oregano essential oil in mitigating the effects of high stocking density on growth performance, carcass traits, physiological stress indicators, gene expression, and intestinal integrity in broiler chickens. A total of, 1250 one-day-old Ross 308 male broiler chicks were randomly allocated to five experimental groups, where each group had five replicates of 50 chicks. Group 1 (control, LSD): 15 chicks/m2 fed a basal diet without feed additive, group 2 (HSD): 20 chicks/m2 fed a basal diet without feed additive, group 3 (BHSD): 20 chicks/m2 fed a basal diet supplemented with B. subtilis (500 mg/kg diet), group 4 (OHSD): 20 chicks/m2 fed a basal diet supplemented with oregano essential oil (300 mg/kg diet), group 5 (CHSD): 20 chicks/m2 fed a basal diet supplemented with oregano essential oil and B. subtilis. At 35 days of age, there was a noticeable improvement in the growth performance of broilers fed CHSD under high stocking density through the increase in body weight gain, dressing percentage, and crude protein digestibility with a decrease in feed conversion rate compared to other groups. Adding CHSD enhanced the state of oxidation and immunity through increasing superoxide dismutase, glutathione peroxidase, and the relative weight of bursa of Fabricius, while decreasing malondialdehyde, in addition to increasing plasma triiodothyronine levels. The microbial structure and morphometric parameters improved in the group that received the CHSD compared to the other groups, where villus height and Lactobacillus population increased, whereas Escherichia coli and Clostridium perfringens population decreased. Glucose transporter 2 (GLUT2), fatty acid transporter 1 (FABP1), and amino acid transferase 1 (CAT1) gene expression levels significantly increased when feeding on oregano essential oil with B. subtilis. In conclusion, combining oregano essential oil and B. subtilis supplements mitigated the effects of high stocking density by enhancing growth performance, antioxidative status, and intestinal integrity, in addition to modifying the genetic expression of genes related to nutrient absorption.

Growth performance, antioxidant status, intestinal morphology, and body composition of Nile tilapia (Oreochromis niloticus) supplemented with essential oils: A meta-analysis

This study aimed to evaluate the effects of dietary supplementation with essential oils (EOS) on growth performance, antioxidant status in blood serum, intestinal morphology, and whole-body composition of Nile tilapia (Oreochromis niloticus) through a meta-analytic approach. The search and collection of scientific articles were conducted using the PRISMA methodology, and 45 full-text scientific articles were obtained. The data used in the meta-analysis were extracted from these 45 documents. The effect size was assessed through weighted mean differences (WMD) using Der-Simonian and Laird random effects models. Dietary supplementation with EOS increased (P < 0.001) final weight, body weight gain, specific growth rate, feed intake, protein efficiency ratio, and survival but decreased (P < 0.001) feed conversion ratio. In blood serum, EOS supplementation decreased (P < 0.001) the concentration of malondialdehyde and increased (P < 0.001) the concentration of catalase, superoxide dismutase, and glutathione peroxidase. In the foregut, midgut, and hindgut, greater (P < 0.01) villus height, villus width, and number of goblet cells were observed in response to EOS supplementation. EOS supplementation increased (P < 0.01) crude protein content and decreased (P < 0.05) crude lipid content in the whole-body. In conclusion, essential oils can be used as a dietary additive to improve growth performance, antioxidant status in blood serum, and intestinal morphology in Nile tilapia. Likewise, supplementation with essential oils increases the protein content and decreases the fat content in the whole-body of Nile tilapia.

Impact of Nanoencapsulated Rosemary Essential Oil as a Novel Feed Additive on Growth Performance, Nutrient Utilization, Carcass Traits, Meat Quality and Gene Expression of Broiler Chicken

This study evaluated the effect of free and nanoencapsulated rosemary essential oil (REO) as an antibiotic alternative in broiler diets on growth performance, nutrient digestibility, carcass traits, meat quality and gene expression. Four hundred twenty day-old commercial broiler chicks (VENCOBB) were randomly allocated to seven dietary treatments, each having four replicates of fifteen chicks. The dietary treatments comprised control (CON) fed a basal diet only, AB (basal diet + 10 mg enramycin/kg), CS (basal diet + 150 mg chitosan nanoparticles/kg), REOF100 and REOF200 (basal diet + 100 mg and 200 mg free REO/kg, respectively), and REON100 and REON200 (basal diet + 100 mg and 200 mg nanoencapsulated REO/kg, respectively). Overall (7-42 d), REON200 showed the highest (p < 0.001) body weight gain (1899 g/bird) and CON had the lowest gain (1742 g/bird), while the CS, REOF100 and REOF200 groups had a similar gain, but lower than that of the AB and REON100 groups. Feed intake was not affected by dietary treatments. Overall, the feed efficiency increased (p = 0.001) by 8.47% in the REON200 group and 6.21% in the AB and REON100 groups compared with the CON. Supplementation of REO improved (p < 0.05) dry matter and crude protein digestibility, with the highest values in REON100 and REON200. Ether extract, crude fiber, calcium and phosphorus digestibility values showed no difference among the groups. The dressing, breast, thigh % increased (p < 0.05) and abdominal fat % decreased (p < 0.001) more in the REON200 group than with other treatments and CON. In breast meat quality, water holding capacity and extract reserve volume increased (p < 0.05) while drip loss and cholesterol content decreased (p < 0.05) in REON100 and REON200. No change was observed in the breast meat color among dietary treatments and CON. The REON100 and REON200 groups had reduced (p < 0.05) meat lipid peroxidation as depicted by the decreased levels of TBARS, free fatty acids and peroxide value compared to other treatments and CON. The expression of the Mucin 2, PepT1 and IL-10 genes was upregulated (p < 0.001) and TNF-α downregulated (p < 0.001) by dietary addition of REO particularly in the nanoencapsulated form compared with the CON. In conclusion, nanoencapsulated REO, especially at 200 mg/kg diet, showed promising results as an antibiotic alternative in improving the performance, nutrient digestibility, carcass traits, meat quality and upregulation of growth and anti-inflammatory genes.

A meta-analysis of essential oils as a dietary additive for weaned piglets: Growth performance, antioxidant status, immune response, and intestinal morphology

This study aimed to evaluate the effects of dietary supplementation with EOS on growth performance, blood serum antioxidant status, immune response, and intestinal morphology of weaned piglets using a meta-analytical approach. The database included 31 studies from which the response variables of interest were obtained. All data were analyzed using a random effects model, and results were expressed as weighted mean differences between treatments supplemented with and without EOS. EOS supplementation increased (P < 0.001) average daily feed intake, average daily gain, and final body weight and decreased (P < 0.001) feed conversion ratio and diarrhea incidence. Lower (P = 0.001) serum malondialdehyde content and higher (P < 0.05) serum concentrations of superoxide dismutase, catalase, glutathione peroxidase, and total antioxidant capacity were observed in response to the dietary inclusion of EOS. EOS supplementation increased (P < 0.001) the serum concentration of immunoglobulins A, G, and M and decreased (P < 0.05) the serum concentration of tumor necrosis factor-α, interleukin-1β, and interleukin-6. Greater (P ≤ 0.001) villus height (VH) was observed in the jejunum and ileum in response to the dietary inclusion of EOS. However, EOS supplementation did not affect (P > 0.05) crypt depth (CD) and decreased (P < 0.001) the VH/CD ratio in the duodenum, jejunum, and ileum. In conclusion, essential oils can be used as a dietary additive to improve growth performance and reduce the incidence of diarrhea in weaned piglets and, at the same time, improve the antioxidant status in blood serum, immune response, and intestinal morphology.

Effect of a microencapsulated phyto/phycogenic blend supplementation on growth performance, processing parameters, meat quality, and sensory profile in male broilers

Powered by consumer taste, value, and preferences, natural products including phytogenics and algae are increasingly and separately used in the food systems where they have been reported to improve growth performance in poultry and livestock. The present study aimed to determine the effects of a new feed additive, microencapsulated NUQO© NEX, which contains a combination of phytogenic and phycogenic, on broiler growth performance, blood chemistry, bone health, meat quality and sensory profile. Male Cobb500 chicks (n = 1,197) were fed a 3-phase feeding intervals; 1-14d starter, 15-28d grower, and 29-40d finisher. The dietary treatments included a corn-soy basal Control (CON), basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 28d then 75 g/ton from d 28 to 40 (NEX75), and basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 40d (NEX100). The NEX100 supplemented birds had 62 g more BWG increase and 2.1-point improvement in FCR compared with CON in the finisher and overall growth phase (p < 0.05), respectively. Day 40 processing body weights and carcass weights were heavier for the NEX100 supplemented birds (p < 0.05). The incidences of muscle myopathies were also higher in NEX treatments, which could be associated with the heavier weights, but the differences were not detected to be significant. The NEX75 breast filets had more yellowness than other dietary treatments (p = 0.003) and the NEX 100 treatment reduced the levels of breast filet TBARS at 7 days-post harvest (p = 0.053). Finally, both NEX treatments reduced the incidence of severe bone (tibia and femur) lesions. In conclusion, the supplementation of the phytogenic NUQO© NEX improved finisher performance parameters, whole phase FCR, processing carcass weights, and breast filet yellowness, at varying inclusion levels.

Protective effects of feed additives on broiler chickens exposed to aflatoxins-contaminated feed: a systematic review and meta-analysis

Aflatoxin contamination in feed is a common problem in broiler chickens. The present systematic review and meta-analysis examined the impact of aflatoxin-contaminated feed and the efficacy of various feed additives on the production performance of broiler chickens fed aflatoxin-contaminated feed (AF-feed). A total of 35 studies comprising 53 AF-feed experiments were selected following PRISMA guidelines. Feed additives included in the analyses were toxins binder (TB), mannan-oligosaccharides (MOS), organic acid (OA), probiotics (PRO), protein supplementation (PROT), phytobiotics (PHY), and additive mixture (MIX). Random effects model and a frequentist network meta-analysis (NMA) were performed to rank the efficacy of feed additives, reported as standardized means difference (SMD) at 95% confidence intervals (95% CI). Overall, broiler chickens fed AF-feed had significantly lower final body weight (BW) (SMD = 198; 95% CI = 198 to 238) and higher feed conversion ratio (SMD = 0.17; 95% CI = 0.13 to 0.21) than control. Treatments with TB, MOS, and PHY improved the BW of birds fed AF-feed (P < 0.05) to be comparable with non-contaminated feed or control. Predictions on final BW from the broiler-fed aflatoxin-contaminated diet were 15% lower than the control diet. Including feed additives in the aflatoxins diet could ameliorate the depressive effect. Remarkably, our network meta-analysis highlighted that TB was the highest-performing additive (P-score = 0.797) to remedy aflatoxicosis. Altogether, several additives, especially TB, are promising to ameliorate aflatoxicosis in broiler chickens, although the efficacy was low regarding the severity of the aflatoxicosis.

Effects of essential oils on egg production and feed efficiency as influenced by laying hen breed: A meta-analysis

Background and Aim

Successful rearing of laying hens to achieve optimal egg production is an endeavor that often faces various constraints and challenges, such as infectious diseases, environmental stressors, and fluctuations in feed quality. The incorporation of essential oils (EOs) into the diet of laying hens has attracted considerable attention in recent years. Therefore, our study aimed to evaluate the efficacy of EO inclusion in laying hen diets by considering the effects of production phase and breed on performance, egg quality, serum biochemistry, gut health, and antioxidant activity.

Materials and Methods

The articles were obtained from the Web of Science, Scopus, Science Direct, and PubMed using the search terms "essential oils," "laying hens," and "phytobiotics." Data from 27 articles and 71 experiments were grouped according to laying hen production phase and breed in the database. The EO levels ranged from 0 to 1000 mg/kg, with thymol and carvacrol being the major EOs. A mixed model was used to analyze the data. Random effects were applied to the treatment, and fixed effects were applied to EO level, production phase, and breed.

Results

Egg production, feed intake, feed efficiency, eggshell quality, villus height, crypt depth, superoxide dismutase, and glutathione peroxidase levels increased linearly (p = 0.05) and egg weight and mass increased quadratically (p < 0.05) with increasing EO concentrations. An interaction was observed between the EO level egg production and feed conversion ratio (p = 0.05). Serum glucose, cholesterol, and malondialdehyde levels decreased with increasing EO concentrations (p < 0.05).

Conclusions

The inclusion of EOs effectively increased egg production, feed efficiency, egg weight, egg mass, eggshell quality, oxidative enzymes, and intestinal health. In addition, the proportion of dietary EOs in lightweight laying hens was higher than that in semi-heavy-weight laying hens in improving egg production and feeding efficiency.

Impacts of red clover and sainfoin silages on the performance, nutrient utilization and milk fatty acids profile of ruminants: A meta-analysis

Inclusion of plants rich in secondary metabolites into grass ensiling offers multiple benefits for ruminants, from improving productive performance to health-promoting effects as well as helping to reduce environment pollution. The present meta-analysis summarizes the dietary inclusion levels of red clover silage (RCS) and sainfoin silages (SS) as well as the types of silages fed to dairy cows and small ruminants. A total of 37 in vivo studies (26 articles in dairy cows and 11 articles in small ruminants) were aggregated after being strictly selected using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A mixed model methodology was used to examine our objectives. This method declares the subject 'study' as random effects and 'inclusion level' as fixed effects. Results indicated that RCS proportion was not associated with nutrient digestibility except for a quadratic effect (p < 0.05) on neutral detergent fibre digestibility. Higher RCS inclusion linearly increased (p < 0.05) nitrogen (N) intake but had no effect on dairy cows' production. Increasing RCS proportion altered milk fatty acid profile where the concentration of conjugated linolenic acid (CLA), C18:3 α-linolenic acid (ALA) and C18:0 linearly increased (p < 0.01). In small ruminants, SS proportion had no relationship with nutrient digestibility, N metabolism and growth performance (p > 0.05). However, a combination of dietary RCS + SS resulted in significantly higher (p < 0.05) CLA and ALA concentration in cow milk and average daily gain (ADG) in small ruminants compared to diets composed from either grass silage or alfalfa silage. Altogether, this meta-analysis highlights the synergistic effects of a combination of SS + RCS inclusion in improving milk fatty acids (FA) profile of dairy cows and ADG of small ruminants.

The relationship between G1 (c.260 G>A) and G4 (c.721 G>A) polymorphisms in the GDF9 gene and the litter size of sheep: A meta-analysis study

Objective

The results of G1 and G4 polymorphisms as litter-size (LS) markers of ewes remain contradictory. The aim was to evaluate the impact of G1 (c.260 G>A) and G4 (c.721 G>A) polymorphisms on the LS of sheep by synthesizing data from multiple previous studies.

Methods

Data were extracted from 14 eligible articles. The genotypes of G1 and G4 polymorphisms were homozygous wild-type (WW), heterozygous (WM), and homozygous mutant-type (MM). The standardized mean difference (SMD) method using random effect models was employed to determine the effect size of G1 and G4 polymorphisms on LS under dominant, recessive, additive, and co-dominant genetic models. Heterogeneity was analyzed with the I2 statistic index. Publication bias was depicted with funnel plots and tested by Egger's and Begg's tests.

Results

The study showed that the correlation between G1 polymorphism and LS in sheep was not significant (p > 0.05) under all genetic models. The influence of G4 polymorphism on the LS of sheep was found significantly (p < 0.05) under dominant [SMD = 0.28, I2 = 0% (no heterogeneity)] and co-dominant [SMD = -0.14, I2 = 36% (moderate heterogeneity)] genetic models. The WM genotype of G4 polymorphism increased LS, while the MM genotype reduced LS in sheep. Publication bias among G1 and G4 polymorphism studies was absent in all genetic models.

Conclusion

Thus, the study revealed that G4 polymorphism could be a potential genetic marker for LS in ewes. On the contrary, G1 polymorphism has no association with the LS of ewes.

Relationships between dietary rumen-protected lysine and methionine with the lactational performance of dairy cows - A meta-analysis

OBJECTIVE

Our objective was to examine the relationships of supplemental rumen-protected lysine (RPL) or lysine + methionine (RPLM) on lactational performance, plasma amino acids (AA) concentration, and nitrogen use efficiency of lactating dairy cows by using a meta-analysis approach.

METHODS

A total of 56 articles comprising 77 experiments with either RPL or RPLM supplementation were selected and analyzed using a mixed model methodology by considering the treatments and other potential covariates as fixed effects and different experiments as random effects.

RESULTS

In early lactating cows, milk yield was linearly increased by RPL (β1 = 0.013; p<0.001) and RPLM (β1 = 0.014; p<0.028) but 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM) (kg/d) was increased by only RPL. RPL and RPLM did not affect dry matter intake (DMI) but positively increased (p<0.05) dairy efficiency (Milk yield/DMI and ECM/DMI). As a percentage, milk fat, protein, and lactose were unchanged by RPL or RPLM but the yield of all components was increased (p<0.05) by feeding RPL while only milk protein was increased by feeding RPLM. Plasma Lys concentration was linearly increased (p<0.05) with increasing supplemental RPL while plasma Met increased (p<0.05) by RPLM supplementation. The increase in plasma Lys had a strong linear relationship (R2 = 0.693 in the RPL dataset and R2 = 0.769 in the RPLM dataset) on milk protein synthesis (g/d) during early lactation. Nitrogen metabolism parameters were not affected by feeding RPL or RPLM, either top-dress or when supplemented to deficient diets. Lactation performance did not differ between AA-deficient or AA-adequate diets in response to RPL or RPLM supplementation.

CONCLUSION

RPL or RPLM showed a positive linear relationship on the lactational performance of dairy cows whereas greater improvement effects were observed during early lactation. Supplementing RPL or RPLM is recommended on deficient-AA diet but not on adequate-AA diet.

Comparative effects of medium-chain fatty acids or phytobiotics-based feed additives on performance, caecum microbiota, volatile fatty acid production and intestinal morphology of broilers

Antibiotic growth promoters have been utilized in broiler nutrition to alleviate the negative effects of the pathogenic microbes to promote performance. However, after the prohibition of antibiotics because of the increasing disclosure related to public health issues, various products have been developed as alternatives. This study was carried out to determine the effects of medium-chain fatty acids (MCFAs) or phytobiotics (essential oils [EOs] and alkaloids [ALKs]), blended feed additives on the growth performance, jejunum histomorphology, and cecal microbiota of broiler chickens. A total of 765 male Ross 308 chicks were randomly distributed into 5 experimental groups, each having 9 replicates with 17 chicks. The experimental procedures were as follows: a control group without supplementation (T1); control group+ MCFAs and EOs blend (T2); control group+ different EOs blend (T3); control group+ ALK sanguinarine (T4); and control group+ EOs and ALK piperine mixture (T5). The results showed that, broilers fed with MCFAs blended with EOs had significantly greater body weight gain during overall period in comparision to the control and T3 groups. Further, only MCFAs blended with EOs group significantly improved jejnum morphology in comparison with the control group (p ≤ 0.05). Besides, the MCFAs blended with EOs group significantly elevated propionate, acetate and butyrate concentration, and decreased the concentration of branch chain fatty acids in caecum (p ≤ 0.05). The results indicated that, the combination of MCFAs and EOs seems to have improvement effects and could be preferred as an efficient feed additive in broiler production.

Efficacy of Bacillus subtilis to replace in-feed antibiotics of broiler chickens under necrotic enteritis-challenged experiments: a systematic review and meta-analysis

Necrotic enteritis (NE) and coccidiosis are among the most prevalent infectious diseases in broiler chickens, contributing to large profitability losses. Bacillus subtilis is a promising direct-fed probiotic to counter various pathogens infection in broiler chickens. Here, we performed a meta-analysis to investigate the effects of B. subtilis on broiler chickens performance. A total of 28 studies were selected according to a PRISMA checklist. Random-effect model and mixed-effect model of meta-analysis were fitted to estimate the overall effects of B. subtilis (BS) treatment compared to either the control group (CON) or NE-infected group (NEinf) as a baseline. Hedges' g effect size and its variance were used as estimators of standardized mean difference (SMD) calculation where the results were presented at a 95% confidence interval (95% CI) of the SMD. Overall, NEinf broiler chickens depressed (P < 0.01) body weight (BW), average daily gain (ADG), and feed intake, and elevated (P < 0.01) feed conversion ratio (FCR). Treatment with BS improved ADG and final BW of NEinf with no difference (P = 0.15) between BS and antibiotics (AB), indicating that they had comparable efficacy to treat NE in broiler chickens. BS supplemented to uninfected CON (BSS) improved (P < 0.01) final BW, ADG, and FCR. Compared to CON, BS, and AB failed to recover the FCR but these treatments decreased (P < 0.01) FCR when compared to the NEinf group with similar efficacy (P = 0.97). As expected, NEinf birds had a higher mortality rate (P < 0.01) and higher lesion score (P < 0.01) compared to CON, and treatment using AB and BS successfully decreased (P < 0.01) the mortality rate and lesion score. Compared to BS, AB was more effective to lower (P = 0.01) mortality rate, but comparable (P = 0.65) to minimize lesion score. To conclude, B. subtilis could be an effective natural additive to replace in-feed antibiotics in broiler chickens challenged with C. perfringens. However, the efficacy to reduce mortality rate was better with antibiotics treatment.

Effect of Chitosan on Ruminal Fermentation and Microbial Communities, Methane Emissions, and Productive Performance of Dairy Cattle

This study aimed to expand the knowledge about the activity and mode of action of CHI on methanogenesis and rumen microbial populations in vivo. A total of 16 lactating dairy cows were distributed in two groups, one of them receiving 135 mg CHI/kg body weight daily. The effect on productive performance, milk composition, fermentation efficiency, methane emissions, microbial protein synthesis, and ruminal microbial communities was determined. Supplementation with CHI did not affect rumen microbial diversity but increased the relative abundance (RA) of the bacteria Anaeroplasma and decreased those of rumen ciliates and protozoa resulting in a shift towards a lower acetic to propionic ratio. However, no effect on milk yield or methane intensity was observed. In conclusion, supplementing 135 mg CHI/kg body weight increased the RA of Anaeroplasma and decreased those of rumen ciliates and protozoa, both being related to fiber degradation in the rumen in different ways and resulted in a shift of ruminal fermentation towards more propionate proportions, without affecting CH4 emissions, milk yield, or milk composition. Further research with higher doses would be necessary to assess the potential use of this additive as a methane inhibitor.

Dietary oregano aqueous extract improves growth performance and intestinal health of broilers through modulating gut microbial compositions

BACKGROUND

Intestinal health plays a pivotal role in broiler chicken growth. Oregano aqueous extract (OAE) effectively exerts anti-inflammatory and antibacterial effects. However, the protective effects of OAE on intestinal health in broilers and the underlying mechanism remain unclear. This study aimed to investigate the potential effects of OAE on growth performance, the gut microbiota and intestinal health. A total of 840 1-d-old male and female broilers (Arbor Acres) were randomly allocated into 6 groups as follows: basal diet (Con), Con + antibiotics (Anti, colistin sulfate 7 g/kg, roxarsone 35 g/kg), Con + 400, 500, 600 and 700 mg/kg OAE (OAE400, OAE500, OAE600 and OAE700). Subsequently, fermentation in vitro together with oral administration trials were carried out to further assess the function of OAE on intestinal health of broilers.

RESULTS

Dietary 700 mg/kg OAE supplementation resulted in an increase (P < 0.05) in body weight and a decrease (P < 0.05) in feed conversion ratio when compared with the control during d 22 to 42 of the trial. OAE addition resulted in lower (P < 0.05) jejunal crypt depth and mRNA expression of IL-4 and IL-10 at d 42. In addition, dietary OAE addition increased the abundance of Firmicutes (P = 0.087) and Lactobacillus (P < 0.05) in the cecum, and increased (P < 0.05) the content of acetic acid and butyric acid. In the in vitro fermentation test, OAE significantly increased (P < 0.05) the abundance of Lactobacillus, decreased (P < 0.05) the abundance of unspecified_Enterobacteriaceae, and increased the content of acetic acid (P < 0.05). In the oral administration trial, higher (P < 0.05) IL-4 expression was found in broilers when oral inoculation with oregano fermentation microorganisms at d 42. And SIgA content in the ileum was significantly increased (P = 0.073) when giving OAE fermentation supernatant.

CONCLUSIONS

Dietary OAE addition could maintain intestinal health and improve growth performance through enhancing intestinal mucosal immunity and barrier function mediated by gut microbiota changes.

Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis

BACKGROUND

Reducing Salmonella infection in broiler chickens by using effective and safe alternatives to antibiotics is vital to provide safer poultry meat and minimize the emergence of drug-resistant Salmonella and the spread of salmonellosis to humans. This study was to first evaluate the protective efficacy of feeding coated essential oils and organic acids mixture (EOA) on broiler chickens infected with Salmonella Enteritidis (S. Enteritidis, SE), and then its action mechanism was further explored.

METHODS

A total of 480 1-day-old Arbor Acres male chickens were randomly assigned into five treatments with six replicates, including non-challenged control fed with basal diet (A), SE-challenged control (B), and SE-infected birds fed a basal diet with 300 mg/kg of EOA (BL), 500 mg/kg of EOA (BM) and 800 mg/kg of EOA (BH), respectively. All birds on challenged groups were infected with Salmonella Enteritidis on d 13.  RESULTS: Feeding EOA showed a reversed ability on negative effects caused by SE infection, as evidenced by decreasing the feed conversion rate (FCR) and the ratio of villus height to crypt depth (VH/CD) (P < 0.05), obviously decreasing intestinal and internal organs Salmonella load along with increasing cecal butyric acid-producing bacteria abundance (P < 0.05). Moreover, supplemental different levels of EOA notably up-regulated claudin-1 (CLDN-1), occludin (OCLN), zonula occludens-1 (ZO-1), mucin-2 (MUC-2), fatty acid binding protein-2 (FABP-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), myeloid differential protein-88 (MyD88) and interleukin-6 (IL-6) mRNA levels in the ileum of the infected chickens after challenge, whereas down-regulated toll-like receptor-4 (TLR-4) mRNA levels (P < 0.05). Linear discriminant analysis combined effect size measurements analysis (LEfSe) showed that the relative abundance of g_Butyricicoccus, g_Anaerotruncus and g_unclassified_f_Bacillaceae significantly was enriched in infected birds given EOA. Also, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed that alpha-linolenic acid metabolism, fatty acid metabolism and biosynthesis of unsaturated fatty acids were significantly enriched in the EOA group.

CONCLUSION

Our data suggest that the essential oils and organic acids mixture can be used as an effective strategy to ameliorate and alleviate Salmonella Enteritidis infection in broilers.

Effect of water supplementation of Magic oil at different growing periods on growth performance, carcass traits, blood biochemistry, and ileal histomorphology of broiler chickens

Natural antibiotic substitutes have recently been used as growth promoters and to combat pathogens. Therefore, this study aimed to assess the effects of adding Magic oil (nano-emulsified plant oil) at different growing periods on growth performance, histomorphology of the ileum, carcass traits, and blood biochemistry of broiler chickens. A total of 432-day-old Ross 308 chicks were randomly assigned to 1 of 6 water supplementation treatment groups based on growing periods, with 4 groups of Magic oil programs compared to probiotic (Albovit) as a positive control and nonsupplemented group as a negative control, with 9 replicates each with 8 birds (4♂ and 4♀). The periods of adding Magic oil Magic oil were 35, 20, 23, and 19 d for T1, T2, T3, and T4, respectively. Birds' performance was evaluated during 0 to 4, 4 to 14, 21 to 30, 30 to 35, and overall days old. Carcass parameters, blood chemistry, and ileal histomorphology were examined on d 35. The findings showed that birds in the T4 group of the Magic oil supplementation program (from 1 to 4 and 21 to 35 d of age) consumed 1.82% and 4.20% more food, gained 3.08% and 6.21% more, and converted feed to meat 1.39% and 2.07% more than Albovit and negative control, respectively, during the experiment (1-35). Magic oil particularly T1 (Magic oil is supplemented throughout the growing period) and T4 programs improved intestinal histology compared to the negative control. There were no changes (P > 0.05) between treatments in carcass parameters and blood biochemistry. In conclusion, water supplementation with Magic oil for broilers improves intestinal morphometrics and growth performance similar to or better than probiotic, especially during brooding and overall periods. Further studies are needed to evaluate the effect of adding both nano-emulsified plant oil and probiotics on different parameters.

The Effect of In Ovo Administration of Rosemary Essential Oil on Hatchability, Relative Hatching Weight, and Embryo Mortality Rate in Japanese Quail (Coturnix coturnix japonica)

This study aimed to determine the effects of air sac injection of rosemary essential oil at different concentrations in ovo in quail eggs on hatching rate, relative chick weight at hatching, and embryonic mortality rate. A total of 1060 Japanese quail eggs were divided into four groups: negative control (non-injected), positive control (30 µL sterile distilled water/egg), and two treated groups with 1 and 3 µL oil/egg, respectively. The concentration of 3 µL/egg showed a toxic effect on embryonic development, as revealed by the significantly (p = 0.015) higher post-injection mortality rate (18.21%) compared to 1 µL/egg with 8.3%. Furthermore, hatchability was significantly increased (p = 0.0001) with 1 µL/egg compared to 3 µL/egg with 69.1% and 44.48%, respectively. No significant difference was observed between the concentration of 1 µL/egg and the control groups (p = 0.822). Both l and 3 µL essential oil/egg significantly enhanced (p = 0.0001) relative chick weight at hatching by 67.14% and 70.32%, respectively, compared to the control groups. In conclusion, injecting eggs with 1 µL oil/egg showed positive effects both on hatching and relative chick weight. The concentration of 3 µL/egg was revealed to be toxic, with dramatic effects on embryonic survival.

In Vitro Assessment of Antimicrobial Activity of Phytobiotics Composition towards of Avian Pathogenic Escherichia coli (APEC) and Other E. coli Strains Isolated from Broiler Chickens

Escherichia coli infections (including APEC) in broiler chickens are not only a health and economic problem of the flock, but also a significant health threat to poultry meat consumers. The prophylactic and therapeutic effects of the phytobiotic composition on E. coli in broiler chickens were previously described. However, most of the data were related to the reference strains (for both in vitro and in vivo models). Based on the previous studies in human and animals, E. coli strains seem to be multidrug resistance. This, in turn, makes it necessary to develop effective alternative methods of treating this type of infection already at the stage of poultry production. In the present study, the antibacterial activity against various strains of E. coli (including APEC) was assessed for two innovative phytobiotics mixtures: H1, containing thymol, menthol, linalool, trans-anethole, methyl salicylate, 1,8-cineol, and p-cymene; H2, in addition to compounds from H1, containing terpinen-4-ol and γ-terpinene. The unique mixtures of phytobiotics used in the experiment were effective against various strains of E. coli, also against APEC, isolated from broiler chickens from traditional industrial breeding, as well as against those showing colistin resistance. The minimum inhibitory concentration (MIC) values for these unique mixtures were: For H1 1:512 for APEC and non-APEC E. coli strains isolated from day old chicks (DOCs), 1:512 for non-APEC, and 1:1024 for non-APEC isolated from broilers sample. For mixture H2, MIC for APEC from both type of samples (DOCs and broilers) was 1:1024 and for non-APEC (DOCs and broilers) was 1:512. The results suggest that phytobiotic compositions used in this study can be successfully used as a natural alternative to antibiotics in the treatment of E. coli infections in broiler chickens. The promising results may be a crucial point for further analyses in broiler flocks exposed to E. coli infections and where it is necessary to reduce the level of antibiotics or completely eliminate them, thus reducing the risk of foodborne infections.

Effect of dietary essential oil of oregano on performance parameters, gastrointestinal traits, blood lipid profile, and antioxidant capacity of laying hens during the pullet phase

Many benefits have been found in supplementing essential oils such as oregano oil (EOO) to poultry, including increased body weight gain, antioxidant activity, and better gastrointestinal morphology. However, few studies tested the influence of EOO supplementation on laying hens and reported conflicting results regarding its efficacy in improving their health and performance. Therefore, we aimed to explore the effects of dietary EOO on performance, gastrointestinal (GIT) traits, blood lipid, and antioxidant capacity in laying hens during the rearing phase. A total of 300-day-old Hy-line-Brown chicks were used, and treatment diets consisted of corn-soybean based either without (CON) or with EOO (Ecodiar®, 0.275 g/kg diet). Birds were randomized across treatments with five pens/treatment and 30-birds/pen. Pen weights and feed rejected were recorded every two weeks (1-17 weeks of age), to calculate daily feed intake (ADFI), body weight (BW), and daily weight gain (ADWG). At 11 and 14 weeks of age, blood samples were collected from 3 birds/pen and analyzed for blood lipids and antioxidant levels, and 5-birds/treatment were euthanized, and GIT traits were tested. Differences in measured parameters across weeks and between treatments were assessed using GLMM with Tukey’s Post hoc test applied to significant results in R 3.3.1 (α set at 0.05). Body weights at weeks 3, 11, 13, and 17 were significantly higher in the EOO group compared to the CON group (all P ≤ 0.05), ADWG was significantly higher in EOO birds compared to CON birds at 9 and 13 weeks old (all P ≤ 0.05), while no significant differences in ADFI were observed between treatments across weeks of the trials. At both 11 and 17 weeks old, triglyceride levels were significantly lower, while high-density-lipoprotein levels were higher in EOO (all P ≤ 0.05). Malondialdehyde levels were lower in the EOO group versus CON (p=0.01), while EOO birds had higher glutathione levels (p=0.01) than CON. Finally, at 12 weeks old, the weight of the entire GIT and empty gizzard were higher in the EOO group versus CON (all P ≤ 0.05), while liver and spleen weights were not significantly different between groups. In conclusion, dietary oregano supplementation exerted promoting effects on the performance of Hy-Line Brown pullets.

Dietary cinnamaldehyde with carvacrol or thymol improves the egg quality and intestinal health independent of gut microbiota in post-peak laying hens

Essential oils have been proven to exert multiple effects on growth performance, production quality, and health status in poultry nutrition, which is dependent on the component and/or dose of essential oils. Diets with the optimal combination of essential oils might be able to improve the performance traits and welfare of laying hens. Therefore, this study was conducted to evaluate the effects of dietary essential oils, which are composed of cinnamaldehyde with carvacrol or thymol, on performance, egg quality, and intestinal health in post-peak laying hens. A total of 384, 50-week-old Hy-line brown laying hens were randomly divided into three groups with 8 replicates of 16 birds each: (1) a basal diet (Ctrl), (2) a basal diet with 100 mg/kg of essential oils consisting of 4.5% cinnamaldehyde with 13.5% carvacrol (CAR+CIN), and (3) a basal diet containing 100 mg/kg of essential oils composed of 4.5% cinnamaldehyde with 13.5% thymol (THY+CIN). The CAR+CIN diet increased the feed consumption from 52 to 55 weeks more than the Ctrl and the THY+CIN diet. Compared with the Ctrl group, the addition of essential oils decreased the dirty egg rate (P = 0.07) in the whole trial period. Regarding egg quality, the birds that received the CAR+CIN and THY+CIN diets increased the eggshell strength (P = 0.099) or Haugh unit (HU, p = 0.03) at 54 weeks, respectively. Supplementation of both CAR+CIN and THY+CIN diets significantly increased the ratio of villus height to crypt depth in the duodenum through increasing villus height and decreasing crypt depth as well as upregulated the mRNA abundances of duodenal occluding and cadherin (P < 0.05). However, the treatment with dietary essential oils did not notably change the proportion of cecal microbiota and bacterial diversity. This study suggested that dietary supplementation of cinnamaldehyde with carvacrol or thymol, the active components of essential oils, could promote egg quality in post-peak laying hens, which might be associated with improved intestinal development and barrier.

Effects of sesame meal bioactive peptides, individually or in combination with a mixture of essential oils, on growth performance, carcass, jejunal morphology, and microbial composition of broiler chickens

The objective of the current study was to investigate the influence of sesame meal bioactive peptides (SMBP) individually or in combination with a mixture of savory (Satureja khuzestanica) and thyme (Thymus daenensis) essential oils (STEO) on growth performance, carcass, jejunal morphology, and cecal microbial composition of broiler chickens. A total number of 250-day-old male Ross broiler chicks were randomly allocated to 5 dietary treatments with 5 replicates per each. Dietary treatments were a corn-soybean meal diet as control; control diet supplemented with 0.5 g/kg of Bacitracin as antibiotic (A); 3 g/kg of SMBP; 0.5 g/kg of STEO; and a combination of 3 g/kg of SMBP and 0.5 g/kg of STEO. Results indicated that inclusion of SMBP + STEO in diet improved body weight gain and feed conversion ratio during 11 to 24 days (P < 0.05). Dietary treatments had no significant effect on the carcass characteristics and internal organs. In jejunal morphology, the villus length (VL) and the ratio of VL to crypt depth (CD) were greater in birds which received SMBP + STEO diets, while CD was lower in broilers fed with SMBP + STEO diet (P < 0.05). Inclusion of SMBP in combination with STEO increased viable count of Lactobacillus while the population of E. coli decreased in birds fed with SMBP + STEO diet (P < 0.05). According to the results of this experiment, it can be concluded that dietary SMBP in combination with STEO had positive effects on the growth performance, jejunal morphometric indices, and cecal microbial composition of broiler chickens.

A Meta-Analysis of Essential Oils Use for Beef Cattle Feed: Rumen Fermentation, Blood Metabolites, Meat Quality, Performance and, Environmental and Economic Impact

The objective of this study was to see how dietary supplementation with essential oils (EOs) affected rumen fermentation, blood metabolites, growth performance and meat quality of beef cattle through a meta-analysis. In addition, a simulation analysis was conducted to evaluate the effects of EOs on the economic and environmental impact of beef production. Data were extracted from 34 peer-reviewed studies and analyzed using random-effects statistical models to assess the weighted mean difference (WMD) between control and EOs treatments. Dietary supplementation of EOs increased (p < 0.01) dry matter intake (WMD = 0.209 kg/d), final body weight (WMD = 12.843 kg), daily weight gain (WMD = 0.087 kg/d), feed efficiency (WMD = 0.004 kg/kg), hot carcass weight (WMD = 5.45 kg), and Longissimus dorsi muscle area (WMD = 3.48 cm2). Lower (p < 0.05) ruminal concentration of ammonia nitrogen (WMD = −1.18 mg/dL), acetate (WMD = −4.37 mol/100 mol) and total protozoa (WMD = −2.17 × 105/mL), and higher concentration of propionate (WMD = 0.878 mol/100 mol, p < 0.001) were observed in response to EOs supplementation. Serum urea concentration (WMD = −1.35 mg/dL, p = 0.026) and haptoglobin (WMD = −39.67 μg/mL, p = 0.031) were lower in cattle supplemented with EOs. In meat, EOs supplementation reduced (p < 0.001) cooking loss (WMD = −61.765 g/kg), shear force (WMD = −0.211 kgf/cm2), and malondialdehyde content (WMD = −0.040 mg/kg), but did not affect pH, color (L* a* and b*), or chemical composition (p > 0.05). Simulation analysis showed that EOs increased economic income by 1.44% and reduced the environmental footprint by 0.83%. In conclusion, dietary supplementation of EOs improves productive performance and rumen fermentation, while increasing the economic profitability and reducing the environmental impact of beef cattle. In addition, supplementation with EOs improves beef tenderness and oxidative stability.

Effects of early growth rate and fat soluble vitamins on glucose tolerance, feed transit time, certain liver and pancreas-related parameters, and their share in intra-flock variation in performance indices in broiler chicken

Three hundred fifty 18-day-old Ross 308 male chicks were used to examine the effects of early growth rate (x̄-3SD, x̄-2SD, x̄-SD, x̄, x̄+SD, x̄+2SD and x̄+3SD) and a fat soluble vitamin (FSV) cocktail on glucose tolerance, whole tract feed transit time (FFT), certain liver, and pancreas related traits as well as their share in intra-flock variance of body weight (BW) at d 42 and feed intake (FI) and feed conversion ratio (FCR) in d 21 to 42 of age. Birds with a greater initial BW (21 d) showed greater FI during d 21 to 42 of age and gained a higher final BW at d 42 of age. The broilers injected with a FSV cocktail consumed more feed with an improved FCR and achieved a noticeable greater BW at d 42 of age compared with the untreated birds (P < 0.05). Blood glucose at 15 min after oral gavageing of a glucose solution was elevated in all birds faster than those with a body weight close to the mean population BW. Lipase activity increased by 9.75% and amylase activity decreased by 14.9% in the birds treated with FSV injections compared with those received no vitamin. Multivariate step-wise regression analysis showed liver percentage as the leading variable accounting for about 75 and 62.77% of BW and FI variance, respectively. Serum cholesterol concentration was the major predictor in a poor model (R2 = 52.07) generated for FCR, explaining 29.3 of the FCR viability (P < 0.150). It was concluded that the slow and fast growing birds within a flock showed the same efficiency in dietary glucose absorbing and blood glucose clearing. The faster-growing birds demonstrated slower FTT. Liver percentage was the major parameter explaining a significant fraction of the intra-flock variance in BW at marketing age and FI during days 21 to 42 d.

Effect of Bacillus species–fermented products and essential oils on growth performance, gut morphology, cecal short-chain fatty acid levels, and microbiota community in broilers

In this study, the effects of Bacillus species–fermented products (synbiotics [SYNs]) and essential oils (EOs) on the growth performance, gut morphology, cecal short-chain fatty acid (SCFA) levels, and microbiota of broilers were investigated. A total of 180 one-day-old unsexed broiler chicks (Ross 308) were randomly assigned to 5 dietary treatments as follows: basal diet (control group), basal diet plus enramycin (10 mg/kg; A group), basal diet plus SYNs (3 × 10¹¹ CFU spore/kg of feed; SYN group), basal diet plus EOs (100 mg/kg; EO group), and basal diet plus SYNs and EOs (SYN + EO group), with 6 replicate cages per treatment group and 6 birds per cage. The SYN+EO treatment resulted in a higher (P = 0.003) average daily gain at 1 to 14 d of age than did the control and EO treatments. SYNs had a significant effect on the average daily gain at 1 to 14 d (P < 0.001) and 1 to 35 d (P = 0.045) of age. EOs had a significant effect on the villus height of the duodenum (P = 0.015) and jejunum (P = 0.027). Superoxide dismutase (SOD) and mucin 2 (MUC2) mRNA expression in the duodenum, jejunum, and ileum in the SYN + EO group was higher (P < 0.001) than that in any of the other groups. The SYN+EO treatment resulted in higher (P < 0.001) 2-methylbutyric acid and 3-methylbutyric acid levels in the cecal digesta of the broilers than did the control treatment. Cecal species evenness in the SYN + EO group was higher (P < 0.001) than that in the control group. The abundance of the phylum Firmicutes in the cecal digesta of the broilers was higher (P < 0.001) in the SYN+EO group than in the control group. SYNs had a significant effect (P < 0.001) on the abundance of the genus Lactobacillus in the cecal digesta of the broilers. The abundance of the genus Lactobacillus was positively associated with 2-methylbutyric acid and 3-methylbutyric acid levels. The 2-methylbutyric acid and 3-methylbutyric acid levels were positively correlated with the villus height of the duodenum and ileum. These results suggest that simultaneous supplementation with SYNs and EOs can increase the average daily gain, improve gut health–associated gene expression, increase SCFA levels, and modulate the gut microbiota composition of broilers.

Meta-analysis of dietary chitosan effects on performance, nutrient utilization, and product characteristics of ruminants

Chitosan (CHI) has been used as a feed additive in ruminant diets, but the effects obtained to date have been varied. This study aimed to evaluate the dietary addition of CHI on performance, nutrient utilization, and product characteristics of ruminants by using a meta-analysis approach. A total of 15 articles that composed of 21 studies and 57 data points were included in the database. Number of articles reported the effects of dietary CHI addition were six on beef cattle, seven on dairy cows, and two papers on sheep. Data analysis was based on the mixed model methodology, in which CHI addition levels were considered as fixed effects whereas different studies were treated as random effects. Results revealed that, across various studies, CHI decreased ruminal acetate proportion (p < 0.05) and increased propionate proportion (p < 0.01). Dry matter and crude protein digestibility were elevated due to CHI addition (p < 0.05). CHI decreased blood cholesterol level (p < 0.05) and increased monounsaturated fatty acid proportion in the milk (p < 0.05). However, CHI addition had no effect on dry matter intake, milk production, and milk efficiency of ruminants. In conclusion, CHI is able to modify rumen fermentation towards a favorable direction, but it limitedly affects performance of ruminants.

Supplementary n-3 fatty acids sources on performance and formation of omega-3 in egg of laying hens: a meta-analysis

A meta-analysis was performed to evaluate the effects of supplementary n-3 polyunsaturated fatty acids (PUFA) sources in the diet on the formation of some important n-3 PUFA contents in eggs and to assess factors contributing to the conversion efficiency of omega-3 in laying hens. A dataset was constructed from 34 studies examining the impact of dietary inclusion with ingredients rich in n-3 PUFA on fatty acids profile and production performance of laying hens. The eligibility criteria were developed to obtain studies reporting required information with sufficient quality. The mixed model methodology was employed where the “study” was set as random effects and fatty acid (FA) supplements as fixed effects. Several factors were included in the models as covariates. Discrete analysis for sources of FA was also performed to compare their effects on FA formation in eggs. Significant linear positive associations were observed between the concentration of α-linolenic acid (ALA), total n-3 PUFA, and the ratio of linoleic acid (LA) to ALA (LA/ALA) in diets with the formation of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), total n-3 PUFA, and n6/n3 ratio in egg (P < 0.05) with different magnitudes. ALA and total n-3 PUFAs concentration had no relationship with cholesterol concentration, feed intake, and egg weight. Prediction models for DHA formation was higher for ALA as predictor variables (slope = 0.482; R² = 0.684) than n-3 PUFAs (slopes = 0.998, R² = 0.628). Significant interactions were found on the level of ALA × FA sources and n-3 PUFA × FA sources. Fish oil (P = 0.0148, R² = 0.732) improved the prediction equation to estimate DHA formation. To conclude, levels of ALA, n-3 PUFA, and the ratio of LA/ALA can be used as predictor variables to estimate the formation of n-3 fatty acids in eggs. It was confirmed that although all n-3 FA sources had a positive correlation on DHA and n-3 PUFA deposition, however, fish oil showed the highest prediction model for DHA formation across all FA sources included in the dataset.

The effects of lactic acid bacteria and yeasts as probiotics on the growth performance, relative organ weight, blood parameters, and immune responses of broiler: A meta-analysis

Introduction: The number of publications in Scopus on this topic increased from less than 50 in 1995 to more than 250 in 2015. In other hand, Inconsistency in results about the correlation between yeast and lactic acid bacteria as probiotics has been evident since the early publications on use in broilers. Methods: A meta-analysis was conducted to determine relationship between lactic acid bacteria and yeast as probiotics to broiler diets on the growth performance, relative organ weight, blood parameters, and immune response of the broiler.  A database was designed based on published data that reported the use of probiotics on the broiler. The method used for selecting articles was based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Articles selected were taken from PubMed, Web of science, Scopus, Google Scholar, and Science direct databases as well as individual. Results: The final database consists of 49 in vivo articles, 93 studies, and 225 treatments. The analysis statement in the system was a PROC MIXED procedure of SAS software. The level of probiotic increased (p <0.001) body weight, body weight gain, and feed intake of broiler. There was a reduction (p <0.01) on feed conversion ratio and mortality on the level probiotic given to broiler. Supplementation of probiotics in broiler diet increased (p <0.001) the weight of liver, spleen, gizzard, bursa of fabricius and carcass yield, while reduced (p<0.001) abdominal fat weight. The probiotic given increased the total of red and white blood cells (both at p < 0.001) but did not affect lymphocyte.  Discussion: It can be concluded the yeast act as supporting agent that serves lactic acid bacteria as probiotic increases the growth performance, relative organ weight, blood parameters, and immune response of the broiler.