Dietary Hydroxytyrosol Supplementation on Growth Performance, Gut Morphometry, and Oxidative and Inflammatory Status in LPS-Challenged Broilers.

This study assessed the effects of hydroxytyrosol (HT) on 8- to 20-day-old broilers challenged with lipopolysaccharide (LPS); 180 Cobb500™ male chicks were randomly assigned to 3 treatment groups, each comprising 10 replicates with 6 birds per replicate. Treatments included a control diet (CON), CON with LPS administration, and CON + LPS supplemented with 10 mg of HT/kg of feed. LPS was administered intraperitoneally on days 14, 16, 18, and 20. Body weight (BW), body weight gain (BWG), and the feed conversion ratio (FCR) were measured. On day 20, ten birds per treatment were slaughtered for analysis. Bursa, spleen, and liver were collected, and their respective relative weight was determined. The jejunum was destined for morphological analyses of villus height (VH), crypt depth (CD), and their ratio (VH:CD), and for mRNA expression of nuclear factor kappa B (NF-κB), catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and interleukins 10 (IL-10), 1 beta (IL-1ß), and 8 (IL-8). HT improved BW, BWG, and FCR, and reduced crypt depth (CD) while increasing the VH:CD ratio in the jejunum. Moreover, HT downregulated mRNA expression of CAT, GPx, IL-10, and IL-1ß. In conclusion, HT enhances broiler growth performance, mitigates jejunal mucosa damage from LPS, and modulates antioxidant and immune responses.

Research Note: Nitrogen-corrected apparent metabolizable energy and standardized ileal amino acid digestibility determination of high-protein dried distiller's grains and corn bran with solubles for broilers.

Metabolism and digestibility trials were performed on broiler chickens to determine 1) nitrogen-corrected apparent metabolizable energy (AMEn) using total excreta collection and 2) standardized ileal amino acid digestibility (SIAAD) using the ileal digesta collection from high-protein dried distillers' grains (HP-DDG) and corn bran with solubles (CBS). The results of the metabolism trial indicated that AMEn values for HP-DDG and CBS were 3,334 kcal/kg and 2,083 kcal/kg on dry matter (DM) basis, respectively. Concerning the HP-DDG, the digestibility trial resulted in the following SIAAD values and digestible concentrations, respectively: 80.33% and 1.09 for Lys, 85.95% and 1.44 for Met + Cys, 75.58% and 1.24 for Thr, 89.58% and 1.66 for Arg, 84.91% and 1.08 for His, 86.37% and 1.35 for Ile, 90.64% and 4.56 for Leu, 85.76% and 1.80 for Val, and 88.67% and 1.90 for Phe. Concerning the CBS, the following SIAAD values and digestible concentrations were measured, respectively: 79.29% and 0.44 for Lys, 89.57% and 0.31 for Met + Cys, 78.89% and 0.40 for Thr, 92.28% and 0.66 for Arg, 87.48% and 0.36 for His, 93.40% and 0.35 for Ile, 92.27% and 1.01 for Leu, 90.97% and 0.51 for Val, and 88.81% and 0.45 for Phe. The digestibility average of CBS is 88.45% for essential amino acids and 85.21% for nonessential amino acids, whereas the digestibility average of HP-DDG is 85.83% for essential amino acids and 83.83% for nonessential amino acids.

Research Note: The influence of different isoleucine: lysine ratios on the growth performance of broiler chickens fed low-protein diets.

Two trials were carried out to assess the effects of different ratios of standardized ileal digestible isoleucine:lysine (SID Ile:Lys) on the growth performance of broiler chickens fed low-protein diets. A total of 1,320 male chickens were distributed in each trial into 6 treatments, with 10 replicates with 22 birds each. A control diet was formulated that satisfied the nutritional requirements of the broilers, and a low-protein diet was formulated with reduced protein content, meeting broiler nutritional requirements, except for the SID Ile levels. Five SID Ile:Lys ratios (56%, 61%, 66%, 71%, and 76%) were obtained by adding l-isoleucine to the low-protein diet. The body weight (BW), body weight gain (BWG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were evaluated from day 1 to day 21 in trial 1, and from day 22 to day 44 in trial 2. ANOVA was performed on the data, and the treatments were compared to the control group using Dunnett's test (P ≤ 0.05). Regression analyses were performed for modeling the variables assessed and the ratios of SID Ile:Lys. There was no significant difference between the treatments on ADFI of birds (P > 0.05). The BW, BWG, and FCR showed a quadratic effect as the SID Ile:Lys ratio increased in low-protein diets in trials 1 and 2 (P ≤ 0.05). In conclusion, the recommended ratio of SID Ile:Lys in low-protein diets for growth performance is around 66% for broiler chickens from 1 to 21 d old and is around 65% for broiler chickens from 22 to 44 d old.

Effects of Hydroxytyrosol Supplementation on Performance, Fat and Blood Parameters of Broiler Chickens.

The study aimed to evaluate the effects of dietary supplementation of hydroxytyrosol (HT) on performance, fat, and blood parameters of broilers. In total, 960 male chicks were distributed into four treatments groups with 12 replicates with 20 birds per pen, with varying HT levels (0, 5, 10, and 50 mg/kg of feed) added to the basal diet from 1 to 42 days old. Feed intake, body weight gain, and feed conversion ratio were evaluated. Enzymes related to liver injury were evaluated in blood. Fatty acid profile and malondialdehyde (MDA) concentration were determined in the breast meat. Dietary supplementation of HT did not improve broilers' performance (p > 0.05). Birds fed 50 mg HT/kg had lower AST, ALT, and GGT concentrations (p ≤ 0.05), whereas broilers fed 5, 10, and 50 mg HT/kg, had lower TBIL concentrations (p ≤ 0.05). Breast meat of broilers fed 50 mg HT/kg had lower lipid content, saturated fatty acid, unsaturated fatty acids, MDA concentrations (p ≤ 0.05), and polyunsaturated fatty acids (p < 0.0001). In summary, supplementation of 5, 10, and 50 mg HT/kg does not improve the performance of broilers, but the dose of 50 mg HT/kg helps the liver against inflammation and improves fat parameters.

The effects of arginine supplementation through different ratios of arginine:lysine on performance, skin quality and creatine levels of broiler chickens fed diets reduced in protein content.

Two trials were carried out to assess the effects of arginine supplementation through ratios of digestible arginine:lysine on growth performance, skin quality and creatine levels in muscle and serum of broiler chickens fed diets reduced in protein content. A total of 1,540 Cobb500 male chickens were distributed into 7 treatments, with 10 replicates with 22 birds each. The experimental diets were based on corn and soybean meal, and a control diet was formulated to satisfy broiler nutritional requirements. A basal diet with reduced protein content was formulated to meet broiler nutritional requirements, except for SID Arg levels. The experimental diets were obtained by adding L-arginine to basal diets, meeting 6 different SID Arg:Lys ratios (94, 100, 106, 112, 118, and 124%). Body weight, body weight gain, average daily feed intake, and feed conversion ratio were evaluated from 01 to 21 d old (trial 1) and from 22 to 44 d old (trial 2). At 21 and 44 d, in trials 1 and 2, respectively, birds were slaughtered to assess skin thickness (ST), skin strength (SS), creatine level in muscle (CRM) and serum (CRS). Data were subjected to ANOVA, and treatments were compared to the control group by Dunnett's test (P ≤ 0.05). Regression analyses were performed to model the variables assessed and the ratios of SID Arg:Lys. The SID Arg:Lys ratios did not affect ADFI of broilers in both trials (P > 0.05), whereas it linearly increased the BW, BWG, and ST, in both trials (P < 0.001). The FCR of broilers linearly decreased, in trial 1 (P = 0.038) and trial 2 (P < 0.001). The CRM of birds had a linear effect (P < 0.001) in trial 1, and a quadratic effect (P = 0.001) in trial 2. The CRS and SS of broilers linearly increased, in trial 2 (P < 0.001). In conclusion, increasing SID Arg:Lys ratios in diets reduced CP enhanced growth performance, skin quality and CR levels in muscle and serum of broiler chickens from 01 to 21 and 22 to 44 d old.

Estimation of optimal ratios of digestible phenylalanine + tyrosine, histidine, and leucine to digestible lysine for performance and breast yield in broilers.

Three experiments were carried out to estimate the optimal ratios of digestible phenylalanine + tyrosine (Phe + Tyr), histidine (His), and leucine (Leu) relative to digestible lysine (Lys) for performance and carcass criteria of Cobb-500 broilers from 8 to 17 d of age. In each experiment, 160 male chicks were allocated to a completely randomized experimental design with eight replicate pens, each receiving five dietary treatments. A common, semi-purified basal diet was formulated to meet all dietary recommendations except for those of the tested amino acids (i.e., Phe + Tyr, His, and Leu). Growth performance and carcass characteristics data were analyzed using various requirement-estimation models, including 95% of the quadratic regression, linear response plateau (LRP; i.e., stepwise regression), LRP-to-quadratic regression ratio; and quadratic broken line (QBL). Graded digestible Phe + Tyr ratios elicited a quadratic response (P < 0.05) in body weight gain and linear responses (P < 0.05) in breast and breast fillet weights. Linear effects (P < 0.05) were also observed when graded ratios of digestible His were fed for feed intake and weight gain, and quadratic responses (P < 0.05) were noted for feed conversion ratio and breast and breast fillet weights and yields. Graded Leu ratios elicited quadratic responses (P < 0.05) in feed intake, weight gain, and breast and breast fillet weight and yield. Based on growth and carcass parameters, the estimated ideal digestible ratios of Phe + Tyr, His, and Leu relative to digestible Lys were 112, 38, and 104%, respectively, for broiler chicks raised from 8 to 17 d of age.