Increased Feed Conversion Ratio Research Articles

250 Effects of premix carriers rich in iron, calcium, or fiber on growth performance of early-growing pigs

Abstract The study was to evaluate the effect of premix carriers rich in iron (sand), calcium (limestone), or fiber (rice hull) on growth performance of early-growing pigs. A total of 215 pigs [initial body weight (BW) = 39.90 ± 5.06 kg) were randomly allotted to 3 dietary treatments containing 2% of different premix carriers: sand, limestone, or rice hull (30% crude fiber) using initial BW and sex as blocks (5 to 6 pigs per pen, 14 pens per treatment). The total Ca in sand, limestone, and rice hull were 4.28, 39.52, and 0.27 %, respectively, with Fe levels of 2.39, 0.20, and 0.05%, respectively. The analyzed total Ca level of the experimental diet containing sand, limestone, or rice hull was 0.69, 0.71, or 1.88 %, the analyzed total P level was 0.49, 0.49, or 0.48 %, and the analyzed total Fe level was 305, 633, or 347 ppm, respectively with 144 ppm of Fe from FeSO4·H2O in each diet. During the 28 d of the experiment, BW, feed disappearance, and fecal scores (ranging from 0 to 3 with 3 indicating watery feces) were recorded. Blood and feces were collected at the end of the experiment to measure the ATTD of dry matter (DM) and CP, serum iron concentration, hemoglobin, and red blood cell count. Data were analyzed by ANOVA using the Mixed Procedure of SAS with different premix carriers as the fixed effect. Limestone reduced the average daily gain (ADG; P < 0.05, 0.871 vs. 0.965 and 0.935 kg/d), increased feed conversion ratio (FCR; P < 0.05, 2.55 vs. 2.33 and 2.36), and aggravated diarrhea severity as reflected by greater fecal scores (P < 0.05, 1.53 vs. 1.18 and 1.19) compared with sand and rice hull as carriers. The ATTD of both DM and CP in pigs fed a premix with sand as a carrier were greater than that in rice hull- or limestone-treated pigs (P < 0.05, DM: 86.7 vs. 77.7 or 74.1%; CP: 86.1 vs. 75.0 or 73.3%). Furthermore, pigs fed a premix containing sand exhibited the greatest serum iron concentrations among treatment groups (sand, limestone, and rice hull: 2.81, 1.93, and 1.69 mg/L). However, no significant difference was observed in red blood cell count or hemoglobin concentrations among groups. In sum, excessive limestone in premix can negatively affect growth performance and fecal consistency, whereas using sand rich in iron as a carrier in premix exerted minimal impact on nutrient digestibility as opposed to limestone or rice hull.

The financial cost of coccidiosis in Algerian chicken production: a major challenge for the poultry sector

ABSTRACT Coccidiosis, caused by parasites of the genus Eimeria, is a significant economic burden to the poultry industry. In this study, we conducted a comprehensive analysis to evaluate the financial losses associated with Eimeria infection in chickens in Algeria, relying on data provided by key stakeholders in the Algerian poultry industry to assess sub-clinical as well as clinical impact. We employed the updated 2020 version of a model established to estimate the cost of coccidiosis in chickens, taking into consideration specific cultural and technical aspects of poultry farming in Algeria. The findings predict economic losses due to coccidiosis in chickens of approximately £86.7 million in Algeria for the year 2022, representing £0.30 per chicken raised. The majority of the cost was attributed to morbidity (74.9%), emphasizing the substantial economic impact of reduced productivity including decreased bodyweight gain and increased feed conversion ratio. Costs associated with control measures made up 20.5% of the total calculated cost, with 4.6% of the cost related to mortality. These figures provide a clear indication of the scope and economic impact of Eimeria infection of chickens in Algeria, illustrating the impact of practices common across North Africa. They underscore the ongoing requirement for effective preventive and control measures to reduce these financial losses while improving productivity and welfare, ensuring the economic sustainability of the Algerian poultry industry.

Multitissue transcriptomics demonstrates the systemic physiology of methionine deficiency in broiler chickens

Methionine (Met) supplementation is common practice in broilers to support nutrition, yet there are gaps in the understanding of its role in systemic physiology. Furthermore, several different Met sources are available that may have different physiological effects. This study evaluated the mode of action of Met deficiency (no Met-supplementation) and supplementation (0.25% DL- or L-Met, 0.41% liquid methionine hydroxy analog-free acid (MHA-FA)), and of Met source (DL-, L- or MHA-FA) in broiler chickens, via host transcriptomics. Biological pathway activation modeling was performed to predict the likely phenotypic effects of differentially expressed genes (DEGs) in tissue samples from the jejunum, liver and breast obtained at 10, 21 and 34/35 d of age from three experiments in a combined analysis. Animal performance data showed that Met deficiency reduced BW, daily BW gain, daily feed intake, and breast yield, and increased feed conversion ratio in all experiments (P < 0.05). Effects of Met deficiency on gene expression were least evident in the jejunum and most evident in the liver and breast, as evidenced by the number of DEG and activated pathways. Activated pathways suggested Met deficiency was associated with inhibited protein turnover, gut barrier integrity, and adaptive immunity functions in the jejunum, that predicted reduced breast yield. There was an interaction with age; in Met-deficient birds, there were 333 DEGs in the jejunum of starter vs finisher birds suggesting young birds were more sensitive to Met deficiency than older birds. In the liver, Met deficiency activated pathways associated with lipid turnover, amino acid metabolism, oxidative stress, and the immune system, whereas in breast, it activated pathways involved in metabolic regulation, hemostasis, the neuronal system, and oxidative stress, again predicting a negative impact on breast yield. In the starter phase, supplementation with DL-Met compared to MHA-FA inhibited gamma-aminobutyric acid activity and oxidative stress in breast tissue. When data from all tissues were integrated, increased expression of a liver gene (ENSGALG00000042797) was found to be correlated with the expression of several genes that best explained variation due to the Met deficiency in jejunum and breast muscle. Some of these genes were involved in anti-oxidant systems. Overall, the findings indicate that impaired growth performance due to Met deficiency results from an array of tissue-specific molecular mechanisms in which oxidative stress plays a key systemic role. Young birds are more sensitive to Met-deficiency and DL-Met was a preferential source of Met than L- or MHA-FA during the starter phase.

Effect of environmental conditions and feed forms on the performance and feeding behavior of group-housed growing-finishing pigs

Aim of study: To investigate the influence of environmental conditions and feed forms on productivity and feeding behavior of growing-finishing pigs.&#x0D; Area of study: Farm located in the North-East of Spain (42°03'11.0"N 2°06'59.5"E).&#x0D; Material and methods: Two trials were conducted (n = 72 pigs each). In the Hot-Temperate/Pelleted trial (HT-P), pigs were half the time under hot conditions (average temperature Ta=28.1℃) and half the time under thermoneutral conditions (Ta=25.5℃) and were fed in pellet. In the Temperate-Hot/Mash trial (TH-M), pigs were half the time under thermoneutral conditions (Ta=23.5℃) and half the time under hot conditions (Ta=27.3℃) and were fed in mash. Productivity and feeding behavior were registered.&#x0D; Main results: Hot conditions during the finishing period in TH-M trial reduced by 118 g/d growth rate and increased feed conversion ratio (2.28 vs. 2.07 kg/kg) compared to HT-P trial (p &lt; 0.001) due to feed intake reduction. Growing pigs under hot conditions and fed in pellet increased total feeder visits (12.8 vs. 7.9 visits/d) and reduced visit size (147 vs. 230 g/visit, p &lt; 0.001); whereas finishing pigs under hot conditions and fed in mash only tended to reduce visit size (308 vs. 332 g/visit, p = 0.08). Pigs fed with mash ate slower (22.8 vs. 34.8 g/min) than pelleted-fed pigs (p &lt; 0.001), independently of environmental conditions.&#x0D; Research highlights: Feed form and environmental conditions affect both feeding behavior and performance of growing-finishing pigs. Unfortunately, due to a design weakness, it was not possible to obtain the sharp effect of both factors.

Effects of probiotic Enterococcus faecium and raw, fermented and sprouted pearl millet based diets on performances, carcass traits, hematological and biochemical indices of broiler chickens

Probiotics, recognized as a safe substitute for antibiotics in the animal industry, have been acknowledged for their growth-enhancing properties. This study assessed the impact of Enterococcus faecium strain NCIMB 11181 and diets incorporating Raw, Sprouted, and Fermented pearl millet on the performance, carcass traits, organ weights, and blood parameters of broiler chickens. In a randomized design, 120 one-day-old Arbor Acre broiler chickens were assigned to five groups: 1) No supplement, negative control (N-con); 2) Control + antibiotics, positive control (P-con); 3) Raw pearl millet + probiotics in drinking water (RPM + PRO); 4) Sprouted pearl millet + probiotics in drinking water (SPM+PRO); 5) Fermented pearl millet + probiotics in drinking water (FPM + PRO). Probiotic supplementation did not significantly impact body weight gain (BWG) but influenced feed intake (FI) (P&lt;0.05). FPM+PRO increased feed conversion ratio (FCR), thigh yield, and drumstick yield. Thymus weight is reduced in the RPM+PRO and SPM+PRO groups compared to the control groups. Serum high-density lipoprotein (HDL) levels decreased (P&lt;0.01) in the P-con and FPM+PRO groups. No treatment effect (P&gt;0.05) was observed on hematological indices. Overall, pearl millet diets supplemented with probiotics demonstrated no adverse effects on the health status of broiler chickens, suggesting their potential as viable alternatives to antibiotics.

Mannanase improves the growth performance of broilers by alleviating inflammation of the intestinal epithelium and improving intestinal microbiota

This experiment aimed to discuss and reveal the effect and mechanism of mannanase on intestinal inflammation in broilers triggered by a soybean meal diet. In this experiment, 384 Arbor Acres broilers at 1 d old were randomly divided into 3 treatment groups. The broilers were fed a corn-soybean meal basal diet, a low-energy diet (metabolizable energy reduced by 50 kcal/kg), and a low-energy diet supplemented with 100 mg/kg mannanase for 42 d. The low-energy diet increased feed conversion ratio from 0 to 42 d, reduced ileal villus height and villus height-to-crypt depth ratio and upregulated the expression of nuclear factor kappa B (NF-κB) in the ileum (P < 0.05). It also reduced cecal short-chain fatty acids (SCFA), such as acetic acid (P < 0.05). Compared with low-energy diets, the addition of mannanase increased body weight at 42 d, promoted the digestibility of nutrients, and maintained the morphology and integrity of the intestinal epithelium of broilers (P < 0.05). In addition, mannanase upregulated the expression of claudin-1 (CLDN1) and zonula occludens-1 (ZO-1) in the jejunum at 21 d, downregulated the expression of ileal NF-κB, and increased the content of isobutyric acid in the cecum of broilers (P < 0.05). The results for the ileal microbiota showed that a low-energy diet led to a decrease in the relative abundance of Lactobacillus reuteri in the ileum of broilers. The addition of mannanase increased the relative abundance of Lactobacillus-KC45b and Lactobacillus johnsonii in broilers. Furthermore, a low-energy diet reduced the relative abundance of Butyricicoccus in the intestine of broilers and inhibited oxidative phosphorylation and phosphoinositol metabolism. Mannanase increased the relative abundance of Odoribacter, promoted energy metabolism and N-glycan biosynthesis, and increased the activities of GH3 and GH18. It is concluded that mannanase could improve the growth performance of broilers by reducing the expression of NF-κB in the ileum, increasing the production of SCFA in the cecum, suppressing intestinal inflammation, balancing the intestinal microbiota, reducing damage to the intestinal barrier, and improving the efficiency of nutrient utilization to alleviate the adverse effects caused by the decrease in dietary energy level.

Rye-grass-derived probiotics alleviate heat stress effects on broiler growth, health, and gut microbiota

The primary aim of this study was to assess the impact of liquid (S-LAB) and lyophilized (L-LAB) probiotics sourced from Rye-Grass Lactic Acid Bacteria on broilers experiencing heat stress. The study involved 240 broiler chicks divided into six groups. These groups included a negative control (Control) with broilers raised at a normal temperature (24 °C) on a basal diet, and positive control groups (S-LAB and L-LAB) with broilers under normal temperature receiving a lactic acid bacteria supplement (0.5 mL/L) from rye-grass in their drinking water. The heat stress group (HS) comprised broilers exposed to cyclic heat stress (5–7 h per day at 34–36 °C) on a basal diet, while the heat stress and probiotic groups (S-LAB/HS and L-LAB/HS) consisted of broilers under heat stress supplemented with the rye-grass-derived lactic acid bacteria. Results indicated that heat stress without supplementation (HS) led to reduced body weight gain, T3 levels, citrulline, and growth hormone levels, along with an increased feed conversion ratio, serum corticosterone, HSP70, ALT, AST, and leptin levels. Heat stress also negatively impacted cecal microbiota, decreasing lactic acid bacteria (LABC) while increasing E. coli and coliform bacteria (CBC) counts. Probiotic supplements (S-LAB/HS and L-LAB/HS) mitigated these effects by enhancing broilers' resilience to heat stress. In conclusion, rye grass-derived S-LAB and L-LAB probiotics can effectively support broiler chickens under heat stress, promoting growth, liver function, hormonal balance, gut health, and cecal microbiome ecology. These benefits are likely mediated through improved gut health.

Effect of day-old chick weight on the response of broilers to high doses of exogenous phytase

A total of 360 Ross 708 male broiler chicks were used in an 8 treatment and 9 replicate cage study to explore the influence of day-old chick weight on the efficacy of exogenous phytase. Treatments were arranged as a 2 × 4 factorial with the factors being diet (a positive (PC) and negative control (NC) varying in nutrient density fed without or with 2 concentrations of exogenous phytase) and chick weight (light; <38.5 g or heavy; >42 g). Chicks were sourced from the same breeder flock, with light and heavy chicks being selected from the naturally occurring heterogeneity in the population. The diets were corn-soybean meal based and the PC was formulated to meet the nutrient requirements of male broiler chicks. The NC was formulated to contain 120 kcal/kg, 0.5, 0.18, and 0.18% less apparent metabolizable energy (AME), crude protein (CP), calcium (Ca), and phosphorus (P), respectively, than the PC. Amino acid (AA) density in the NC was also reduced in line with the reduction in CP and the manufacturers' recommendations for the effect of phytase on amino acid digestibility. Phytase at either 1,000 FYT/kg or 3,000 FYT/kg was added only to the NC to create a total of 4 diets. Water and mash feed were available ad libitum and were offered to 8 replicate cages, each containing 5 chicks. The experiment was conducted over a period of 3 wk and diets were offered in 2 phases (starter from d 1 to 10 and grower from d 11 to 21). Growth performance was monitored at the end of each diet phase and on d 21 ileal digesta were collected for estimation of apparent digestibility of energy (DE), nitrogen (N), Ca, P, dry matter (DM), and AA. There were no statistically significant interactions between diet and day-old chick weight for any of the measured parameters. Light chicks had significantly lower weight gain (approx. 5%) at both d 10 and d 21 compared with heavy chicks. This effect was principally associated with reduced feed intake and there was no significant effect of chick weight on feed conversion ratio (FCR). Chick weight had no effect on ileal nutrient digestibility. The reduction in nutrient density from the PC to the NC generated a significant reduction in weight gain (around 12%) and a significant increase in FCR (1.68 vs. 1.83). This effect was associated with a significant reduction in ileal DE (approximately 150 kcal/kg) and in the digestibility of several AA. Exogenous phytase significantly increased weight gain, reduced FCR and generated a significant increase in the ileal digestibility of energy, N, P, and several AA. Although chick weight and diet did not interact statistically, heavy chicks benefited more than light chicks from high doses of exogenous phytase across almost all measured end points which was confirmed by regression analysis. In conclusion, light chicks have inferior performance outcomes than heavy chicks principally because of reduced feed intake, but putatively not in digestive capacity per se. Exogenous phytase is effective in improving performance and nutrient digestibility in nutrient deficient diets. The effect of chick weight per se, and also breeder flock age, on the utility of supra-nutritional inclusion concentrations of exogenous phytase warrants further study.

The effects of enrofloxacin exposure on responses to oxidative stress, intestinal structure and intestinal microbiome community of largemouth bass (Micropterus salmoides)

Antibiotic residues in the aquaculture environments may lead to antibiotic resistance, and potentially exert adverse effects on health of the non-target organisms and humans. In order to evaluate the effect of enrofloxacin of environmental concentrations on largemouth bass (Micropterus salmoides). Two hundred and seventy largemouth basses (with an average weight of 7.88 ± 0.60 g) were randomly divided into three groups, and separately exposed to 0, 1, 100 μg/L enrofloxacin (Control, ENR1, ENR100) for 30 days to detect the effect of enrofloxacin on the growth performance, oxidative stress, intestinal microbiota structure, inflammatory response and structure of the intestine. The results showed that ENR significantly reduced the final body weight (FBW) and weight gain rate (WGR), and increased feed conversion ratio (FCR) (P < 0.05). The histopathological analysis revealed that the villus width and muscular thickness of anterior intestine were significantly decreased with the increasing of enrofloxacin concentration. The activity of SOD was significantly increased at enrofloxacin stress, while CAT and POD activity were significantly decreased compared to control group (P < 0.05). The activities of lysozyme (LZM), alkaline phosphatase (AKP) and peroxidase (POD) in ENR1 was higher than that of control and ENR100 groups. Enrofloxacin treatment up-regulated the expression IL-1β and TNF-α, and down-regulated IL-10, and decreasing the expression level ZO-1, claudin-1, and occludin. Furthermore, the enrofloxacin treatment significantly decreased the intestinal bacterial diversity (P < 0.05). Exposure to 100 μg/L enrofloxacin obviously increased the relative abundance of Bacteroidota, Myxococcota, and Zixibacteria of fish gut, and reduced Firmicutes; 1 μg/L enrofloxacin considerably increased Bacteroidota, Myxococcota, and Actinobacteria, and reduced Firmicutes. The relative abundance of DTB120 and Elusimicrobiota was positively correlated with the occludin and claudin-1 gene. Taken together, exposure to enrofloxacin inhibited the growth of largemouth bass, influenced intestinal health, and induced dysbiosis of the intestinal microbiota.

Beta-hydroxy-β-methyl butyrate-supplemented diet for broiler chickens is more conducive to dietary protein reduction than a leucine-supplemented diet until 21 days old.

Dietary l-leucine or its metabolite 𝛽-hydroxy-𝛽-methylbutyrate (HMB) has a crucial role in the muscle protein metabolism of broilers during the first few-week growing period. The present study aimed to evaluate the effects of l-leucine (LLPD) or HMB (HLPD) supplementation in a low-protein diet (20%, LPD) until 21 days old on performance, carcass weight, muscle yield and meat quality, as well as intestinal morphometry, in broiler chickens. From days 1-42, LPD decreased body weight gain and feed intake (FI) and increased feed conversion ratio compared to a standard protein diet (22%, SPD). The LLPD and HLPD did not affect FI, but the LLPD decreased the body weight gain and increased the feed conversion ratio compared to the SPD. The LPD group had lower body and muscle weights than other groups. Compared to LPD, HLPD increased dressing percentage. The LPD decreased the serum insulin-like growth factor-1 content compared to the SPD and LLPD. The duodenal villus height of the LPD and LLPD broilers was smaller than those of the SPD and HLPD birds. The HLPD broilers had lower duodenal villus width than the SPD birds. The duodenal crypt depth and ileal mucosal thickness were higher in the HLPD group than in other groups. The HLPD and LLPD enhanced the ileal villus height compared to the SPD. The LLPD and HLPD treatments did not affect meat quality traits compared to the SPD treatment. Dietary HMB could be a conducive approach to reducing dietary protein for broilers until 21 days old. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of synbiotic supplementation on production performance and severity of necrotic enteritis in broilers during an experimental necrotic enteritis challenge

To evaluate the efficacy of synbiotic during a necrotic enteritis (NE) infection, a total of 360 day-old chicks were randomly assigned into 4 experimental groups in a 2×2 factorial setup: control, challenge, synbiotic (1 g/kg), and challenge+synbiotic, with 6 replicates. NE was induced by gavaging 1×104Eimeria maxima oocysts and 1×108 CFU/mL of Clostridium perfringens on d 14 (D14) and D19, 20, and 21, respectively. At D35, the NE challenge decreased the BW gain (P < 0.001) and increased feed conversion ratio (P=0.03), whereas synbiotic supplementation decreased the feed intake (P=0.04). At D21, NE challenge increased gut permeability (P < 0.001), decreased regulatory T cells (Tregs) in the cecal tonsil (CT) (P=0.02), increased Tregs in the spleen (P=0.02), decreased nitric oxide (NO) production in the spleen (P=0.04) and decreased IL-10 expression in CT (P=0.02), whereas synbiotic supplementation increased CD4+:CD8+ T cells in the spleen (P < 0.001) and decreased interferon (IFN)-γ expression in the jejunum (P=0.07), however, synbiotic supplementation during NE challenge decreased mid-gut lesion score (P < 0.001), increased CD4+:CD8+ T cells in CT and decreased IgA production in bile (P < 0.001), compared to the control group. At D28, synbiotic supplementation decreased CD4+:CD8+ T cells in CT (P < 0.001), whereas synbiotic supplementation during NE challenge decreased Tregs in CT (P < 0.001) and increased NO production in the spleen (P=0.04), compared to the control group. At D35, the NE challenge decreased CD4+:CD8+ T cells in the spleen (P=0.03), decreased IgA production in bile (P=0.02), decreased IL-10 expression in CT (P=0.04), and decreased IL-10 (P=0.009), IFN-γ (P=0.03) and inducible nitric oxide synthase (P=0.02) expression in the jejunum, whereas synbiotic supplementation increased Tregs in the spleen (P=0.04), compared to control group. Synbiotic supplementation during the NE challenge decreased both IL-1β (P=0.02) and IFN-γ (P=0.001) expression in CT, compared to the control group. It can be concluded that synbiotic supplementation increases production performance by decreasing mid-gut lesions and enhancing protective immunity against NE, and efficiency of synbiotic could be improved by blending additional probiotics and prebiotics.

Sex-based responses of heat stress and subsequent recovery on the growth performance, metabolic changes, and redox status of broilers at market age.

This experiment investigated the sex responses of heat stress (HS) and subsequent recovery on growth performance, serum metabolic parameters, and redox status. Two hundred 38-day-old broilers were arranged in a completely randomized design with a 2 × 2 (temperatures and sexes) factorial arrangement in five replicates. Broilers were raised at 24 ± 1 °C or 32 ± 1 °C for 3 days and returned to 24 °C for 2 days. The study showed that HS decreased both average daily feed intake (ADFI), average daily gain (ADG), serum total glutathione peroxidase (GPx), and superoxide dismutase (T-SOD). However, it increased feed conversion ratio (FCR), rectal temperature (RT), respiratory rate (RR), serum glucose, blood urea nitrogen (BUN), low-density lipoprotein cholesterol, and the protein carbonyl group (PCG). Male broilers had higher ADFI, ADG, lactic acid (LA), high-density lipoprotein cholesterol (HDL-C), and PCG, but lower FCR, albumin, total antioxidant capacity, T-SOD, and GPx. Temperature and sex significantly interacted with ADFI, ADG, LA, and HDL-C. The effects of HS on RR, RT, glucose, albumin, BUN, PCG, T-SOD, and GPx recovered after 2 days. These results indicate that HS and subsequent recovery affect growth performance, which is accompanied by disturbances in serum nutrient metabolism and abnormalities in redox function and manifested by temporal and gender differences.

Individual and combined effects of deoxynivalenol (DON) with other Fusarium mycotoxins on rainbow trout (Oncorhynchus mykiss) growth performance and health

This study assessed whether the toxicological effects of deoxynivalenol (DON) produced by Fusarium graminearum in rainbow trout (Oncorhynchus mykiss) are altered by the co-exposure to a mixture of toxins produced by Fusarium verticillioides (FUmix). This FUmix contained fusaric acid and fumonisin B1, B2 and B3. Four diets were formulated according to a 2 × 2 factorial design: CON-CON; CON-FUmix; DON-CON; and DON-FUmix. Diets with and without DON contained on average 2700 and 0 µg/kg feed, respectively. The sum of the analysed FUmix toxins was 12,700 and 100 µg/kg feed in the diets with and without FUmix, respectively. The experiment consisted of a 6-week restrictive feeding period immediately followed by a 2-week ad libitum feeding period. Growth performance measurements were taken per feeding period. Histopathological measurements in the liver and gastrointestinal tract (pyloric caeca, midgut and hindgut) were assessed at the end of week 1 and week 6 of the restrictive feeding period and at week 8, the last day of the ad libitum feeding period. During both restrictive and ad libitum feeding, the effects of FUmix and DON on growth performance were additive (no interaction effect; p > 0.05). During the restrictive feeding period, exposure to DON (p ≤ 0.001) and FUmix (p ≤ 0.01) inhibited growth and increased feed conversion ratio (FCR). During this period, DON exposure decreased the protein (p ≤ 0.001) and energy retention (p ≤ 0.05) in the trout. During the ad libitum feeding period, FUmix affected HSI (p ≤ 0.01), while DON exposure reduced feed intake (p ≤ 0.001) and growth (p ≤ 0.001) and increased FCR (p ≤ 0.01). In general, for both liver and intestinal tissue measurements, no interaction effects between DON and FUmix were observed. In the liver, histopathological analysis revealed mild alterations, increased necrosis score by DON (p ≤ 0.01), increased glycogen vacuolization by FUmix (p ≤ 0.05) and decreased percentage of pleomorphic nuclei by FUmix (p ≤ 0.01). DON had a minor impact on the intestinal histological measurements. Over time, some of the liver (glycogen vacuolization score, pleomorphic nuclei; p ≤ 0.01) and intestinal measurements (mucosal fold and enterocyte width; p ≤ 0.01) were aggravated in fish fed the FUmix contaminated diets, with the most severe alterations being noted at week 8. Overall, the co-exposure to FUmix and DON gave rise to additive effects but showed no synergistic or antagonistic effects for the combination of DON with other Fusarium mycotoxins.

Evaluation of Growth Performance, Carcass Composition and Meat Quality of Broiler Chickens Fed Rations Containing Guar Meal and Enzyme Preparations

The study aimed to determine the growth performance, carcass composition, and meat quality of broiler chickens fed rations with different levels of guar meal and feed enzymes. Two hundred and forty one-day-old, sexed chicks were assigned to six equinumerous groups (C4, C8, R4, R8, V4 and V8), with five subgroups each. The birds were fed ad libitum with Starter (1-21 days of life), Grower (22-35 days of life) and Finisher (36-42 days of life) comprised of maize meal, soybean meal, guar meal (4 or 8%), oil, and mineral and vitamin additives, in a two-factor pattern as follows: groups C4 4% guar meal without enzyme preparation, C8 8% guar meal without enzyme preparation, R4 4% guar meal + R enzyme preparation, R8 8% guar meal + R enzyme preparation, V4 4% guar meal + V enzyme preparation, V8 8% guar meal + V enzyme preparation. It was demonstrated that a higher (8%) percentage of guar meal in broiler chicken rations significantly contributed to body weight reduction (by 8%) and increased feed conversion ratio (by 3%). Simultaneously, it reduced the dressing percentage (by 2%) and carcass muscularity (by 3%). Feed rations supplemented with enzymes (R or V) did not improve growth performance and did not impact the dressing percentage, carcass muscularity and fatness. The use of 8% guar meal in broiler chicken feed decreased the crude ash content in the muscles, which, by contrast, increased due to enzyme supplementation. A higher level of guar meal reduced the content (by 4%) and fat quality measured as the ratio between n6:n3 PUFA and the index of AI, TI and HH. The results of the study imply that 4% guar meal inclusion in feed rations for broiler chickens not supplemented with enzymes should be recommended.

Effects of guar gum supplementation in high-fat diets on fish growth, gut histology, intestinal oxidative stress, inflammation, and apoptosis in juvenile largemouth bass (Micropterus salmoides)

The present study aimed to investigate the influence of guar gum supplementation in high-fat diets on the growth performance and intestinal oxidative stress, inflammation, and apoptosis of juvenile largemouth bass. Five isonitrogenous diets were prepared: a control diet (10% crude lipid, C), a high-fat diet (17% crude lipid, HF), and three high-fat diets supplemented with 0.3% guar gum (GG0.3), 1% guar gum (GG1), and 3% guar gum (GG3). Largemouth bass (3.1±0.2 g) were randomly assigned to fifteen tanks (30 fish/tank) and fed for 8 weeks. The results demonstrated that GG0.3 significantly increased specific growth rate (SGR) and increased feed conversion ratio (FCR) compared to HF (P &lt; 0.05). For histology, high-fat diets containing guar gum significantly increased intestinal villus length, villus width, and perimeter ratio, compared with HF (P &lt; 0.05). Compared with Control, HF significantly decreased reduced glutathione (GSH) contents and increased malondialdehyde (MDA) contents in the intestine (P &lt; 0.05). Additionally, HF significantly increased the expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), and cysteine-aspartic proteases 9 (Caspase 9) in the intestine (P &lt; 0.05). Compared to HF, GG0.3 significantly decreased MDA contents, increased GSH contents, and downregulated the expression of IL-1β, TNF-α, and Caspase 3 than diet HF in the intestine (P &lt; 0.05). These results suggest that guar gum can alleviate the adverse effects of high-fat diets on growth and gut health in fish.

Negative consequences of reduced protein diets supplemented with synthetic amino acids for performance, intestinal barrier function, and caecal microbiota composition of broiler chickens

The consequences of feeding broiler chickens with reduced protein (RP) diets for gut health and barrier function are not well understood. This study was performed to elucidate the effect of reducing dietary protein and source of protein on gut health and performance parameters. Four experimental diets included 2 control diets with standard protein levels either containing meat and bone meal (CMBM) or an all-vegetable diet (CVEG), a medium RP diet (17.5% in growers and 16.5% in finisher), and a severe RP diet (15.6% in grower and 14.6% in finisher). Off-sex Ross 308 birds were assigned to each of the 4 diets and performance measurements were taken from d 7 to 42 post-hatch. Each diet was replicated 8 times (10 birds per replicate). A challenge study was conducted on additional 96 broilers (24 birds per diet) from d 13 to 21. Half of the birds in each dietary treatment were challenged by dexamethasone (DEX) to induce a leaky gut. Feeding birds with RP diets decreased weight gain (P < 0.0001) and increased feed conversion ratio (P < 0.0001) from d 7 to 42 compared with control diets. There was no difference between CVEG and CMBM control diets for any parameter. The diet containing 15.6% protein increased (P < 0.05) intestinal permeability independent of the DEX challenge. Gene expression of claudin-3 was downregulated (P < 0.05) in birds fed 15.6% protein. There was a significant interaction between diet and DEX (P < 0.05) and both RP diets (17.5% and 15.6%) downregulated claudin-2 expression in DEX-challenged birds. The overall composition of the caecal microbiota was affected in birds fed 15.6% protein having a significantly lower richness of microbiota in both sham and DEX-injected birds. Proteobacteria was the main phylum driving the differences in birds fed 15.6% protein. At the family level, Bifidobacteriaceae, Unclassified Bifidobacteriales, Enterococcaceae, Enterobacteriaceae, and Lachnospiraceae were the main taxa in birds fed 15.6% protein. Despite supplementation of synthetic amino acids, severe reduction of dietary protein compromised performance and intestinal health parameters in broilers, evidenced by differential mRNA expression of tight junction proteins, higher permeability, and changes in caecal microbiota composition.

Short-term feeding of dietary florfenicol influences gut microbiome and growth performance of fast-growing Silurus meridionalis

Florfenicol is a broad-spectrum antibiotic commonly used in aquaculture to control bacterial infections in fish. However, it may induce perturbation on the gut microbiota, compromising growth and fitness. This study aimed to evaluate the gut microbial community, histological alterations, and growth performance of fast-growing southern catfish Silurus meridionalis larvae fed florfenicol-medicated feed (florfenicol group) at 20 mg/kg biomass per day for 7 days as well as the recovery effects for another 7 days by comparing those of the counterparts fed non-medicated feed (control group). The results showed that dietary florfenicol strikingly affected gut microbial community development and caused community perturbation at day 7, with Proteobacteria enrichment up to 99.3% in the florfenicol group and progressive reductions in microbial diversity and evenness. The antibiotic also rapidly led to enrichments of potential opportunistic pathogens such as Citrobacter, Plesiomonas, and unclassified Aeromonadaceae, which may carry more abundant antibiotic-resistance genes. However, the perturbation effects disappeared gradually after dietary florfenicol withdrawal. Metagenomic predictions revealed an increase in the number of altered microbial functions during the administration of dietary florfenicol and a successive decrease after the withdrawal. Dietary florfenicol had no effect on the gut histological structures and mortalities of southern catfish, but it significantly decreased feed intake. The changes in temporally observed community and function coincided with the commencement of decreased feed intake and increased feed conversion ratio in the florfenicol group, consequent to retarded growth during the dietary administration. These alterations were gradually restorable after the dietary florfenicol withdrawal. This study suggests that short-term feeding of dietary florfenicol disturbs the gut microbiota, potentially impairing fish feeding and feed utilization and, lastly, fish growth performance. The results highlight the importance of responsible and prudent use of florfenicol in aquaculture and the need for more studies to understand the health consequences associated with gut microbiome disturbance resulting from antibiotic use in aquatic animals.

Evaluation of phytase dose effect on performance, bone mineralization, and prececal phosphorus digestibility in broilers fed diets with varying metabolizable energy, digestible amino acids, and available phosphorus concentration

The nutritional composition of diets and the provision of exogenous phytases play important roles in animal performance. Therefore, we evaluated the individual and combined impact of metabolizable energy (ME), digestible lysine (dLys), available phosphorus (avP) and calcium (Ca), and phytase dose (1,000 or 2,000 FTU/kg) on the growth performance, feed efficiency, phosphorus digestibility, and bone ash content of broiler chickens from 10 to 42 d of age. Experimental diets were formulated in a Box-Behnken design to contain various levels of ME (11.9, 12.2, 12.54, or 13.1MJ/kg), dLys (0.91, 0.93, 0.96, or 1.00%) and avP/Ca (0.12/0.47, 0.21/0.58, or 0.33/0.68%). The effect of phytase was expressed in terms of the extra nutrients released. The diets were formulated to have consistent phytate substrate contents (0.28% in average). Body weight gain (BWG) and feed conversion ratio (FCR) were described via polynomial equations (R2=0.88 and 0.52, respectively), with interconnections between variables (ME, dLys, and avP/Ca). No interaction was observed among variables (P > 0.05). Metabolizable energy was the most important factor affecting BWG and FCR (linearly; P < 0.001). Reducing ME content from 13.1 to 11.9 MJ/kg in control diet resulted in a 6.8% decrease in BWG and a 3.1% increase in FCR (P < 0.001). The dLys contents also affected performance linearly (P < 0.001), but to a lesser degree; BWG decreased by 160g when the dLys was reduced by 0.09% units, while the same reduction in dLys increased the FCR by 0.108 points. The inclusion of phytase alleviated the negative effects on feed intake (FI), BWG, and FCR. Phytase improved phosphorus digestibility and bone ash content according to a quadratic relationship. When phytase was added, ME negatively affected FI (r=-0.82,P<0.001), whereas the dLys content was correlated with FCR (r=-0.80,P<0.001). Supplementing phytase allowed the reduction of ME, dLys, and avP-Ca in the diet without affecting performance. The addition of phytase increased of ME, dLys, and avP by 0.20 MJ/kg, 0.04 and 0.18% units for 1,000 FTU/kg and 0.4 MJ/kg, 0.06 and 0.20% units for 2,000 FTU/kg.

Individual and combined effects of hypoxia and hypercapnia on feeding and feed utilization in Nile tilapia (Oreochromis niloticus)

Photosynthesis and respiration exert strong opposing effects on dissolved gases in earthen ponds. During daylight this provides oxygen to the water while removing carbon dioxide. At night, fish, plankton, and sediment respiration consumes the available O2 and produces CO2. This leads to daily conditions that fluctuate between being hyperoxic and hypocapnic during the day, while becoming severely hypoxic and hypercapnic at night. The effects of hypoxia on Nile tilapia have been examined in some detail, but the interacting effects of hypoxia and hypercapnia and fluctuating conditions, have not received any attention. Here we evaluated the effects of daily variations in dissolved O2 and CO2 on the appetite and feed utilization in Nile tilapia using groups reared under normoxic - normocapnic conditions (control, C), diurnal hypoxia (HO), diurnal hypercapnia (HC), or combined diurnal hypoxia and hypercapnia (HO × HC) in a digestibility system. We show that hypoxia and hypercapnia exerted strong individual effects on appetite, specific growth rate, and feed conversion, and that simultaneous hypoxia and hypercapnia amplified these effects. Appetite depression induced by nocturnal hypoxia or hypercapnia was restored at mid-day, but simultaneous exposure resulted in a day-long loss of appetite. Hypoxia and hypercapnia reduced specific growth rates by up to 40% and increased feed conversion ratio by up to 80%, while combined exposure to hypoxia and hypercapnia reduced specific growth rate by >60%. Surprisingly, the digestibility of dry matter, protein, and lipid was improved in groups exposed to single or combined diurnal variation in dissolved oxygen and carbon dioxide. It is unknown whether this is the result of the change in feed intake or represents an adaptive mechanism to satisfy an increase energy demand caused by environmental stress. Overall, we conclude that although Nile tilapia is considered resilient to environmental stress, feeding and feed utilization are strongly influenced by daily fluctuations in dissolved gases.

Effect of partial replacement of concentrate with Prosopis cineraria leaves on nutrient utilization, growth and carcass characteristics of Malpura lambs

A study was aimed to evaluate nutrient utilization, growth, carcass characteristics and meat quality of Malpura lambs fed concentrate mixture containing 10% Prosopis cineraria (Khejri) leaves. Malpura lambs (n=24, ∼3 months old) were distributed into two groups viz., T1 and T2 and fed concentrate mixture with P. cineraria leaves @ 0 and 10% of concentrate, respectively along with basal diet for 90 days. Metabolizable energy (ME) intake was lower (P=0.05) in T2 (1799 Kcal/d) which resulted in lower (P=0.05) average daily gain (131 g) and higher (P=0.03) feed conversion ratio (6.46). Digestibility of dry matter (60.6%), organic matter (63.2%), crude protein (65.4%), ether extract (72.8%), acid digestible fibre (18.1%) and cellulose (19.9%) was decreased and excretion of nitrogen through faeces was increased (P<0.05 resulting in nitrogen per cent of intake. Cooking loss was less (P<0.05), and TBARS (thiobarbituric acid reactive substances) value of meat in T2 (0.46 mg/malonaldehyde/kg meat) was lower (P<0.05) indicating improved oxidative stability. Further, proportion of C18:3 (α-linolenic acid) and total polyunsaturated fatty acid (PUFA) in longissimus thoracis muscle were also higher (P<0.05) in T2 as compared to T1. Hence, it can be concluded that replacement of concentrate mixture with 10% P. cineraria leaves lowered nutrient utilization and increased feed conversion ratio; but it showed positive effects on fatty acid profile and oxidative stability of meat.