Defining optimal dietary starch, oil, and amino acid inclusion levels for broilers experiencing a coccidiosis challenge

Interactive effect of dietary metabolizable energy levels with amino acid density in male broiler chickens: Carcass yield, nutrient intake, digestibility and excretion

This study aimed to assess the interactive effects of ME and digestible amino acid (AA) densities on carcass yield, breast meat quality, nutrient digestibility, and excretion in male broiler chickens. Twelve experimental diets arranged as a 4 × 3 factorial array with 4 levels of ME (standard, -50, -100, -150 kcal) and 3 digestible AA (standard, +3.0 and +6.0%) were offered to 2400 day-old male Ross 308 broiler chickens. Diets were replicated 8 times with 25 birds per replicate, and fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. On day 24, three birds per replicate were euthanized to collect digesta for nutrient digestibility and excreta samples were collected on day 40 for nutrient excretion analysis. On day 42, four birds per replicate were euthanized for carcass yield and quality evaluation. The birds' feed intake, along with calculated ME and AA levels, were used to determine nutrient intake. No interactions were observed between ME and AA densities on carcass characteristics, nutrient digestibility, and excretion (P > 0.05). Reducing ME density linearly increased breast meat yield and decreased abdominal fat, regardless of AA density (P < 0.01). Increasing AA density enhanced breast meat yield but increased white striping and woody breast scores in a linear manner (P < 0.01). Dietary treatments didn't affect ileal digestibility of crude protein and gross energy, except for improved starch digestibility with 6.0% AA density (P < 0.01). Crude fat digestibility decreased linearly with decreased ME density, while reducing ME density linearly decreased fat, calcium, copper, and manganese excretion (P < 0.01). Increasing AA density linearly increased nitrogen excretion, but reduced calcium and iron excretion (P < 0.05). Over the entire production period lower ME and higher AA density increased digestible lysine intake (mg/bird/day; P < 0.01). In summary, these results suggest that dietary ME and AA density, independently, affect carcass yield, breast meat quality, nutrient digestibility, and excretion.

Effects of sodium bisulfate or sodium sesquicarbonate as a sodium source in broiler chicken diets with or without a coccidiosis challenge

Broilers commonly experience stressors such as coccidiosis, a parasitic infection that results in intestinal damage, malabsorption, and performance losses. The poultry industry is exploring alternatives to anticoccidials for controlling coccidiosis, especially through the enhancement of gut health. Sodium bisulfate (NaHSO4; SBS), an acid salt, has been used for many years as a litter acidifier to reduce aerial ammonia in poultry housing. More recently, SBS has shown promise as a feed additive that improves growth performance through enhancing gut health in poultry. Two trials of 1,920 broiler chicks each were raised to 42 d in floor pens. Chicks were randomly divided into 1 of 4 treatments (480 chicks/treatment) on d 0 that utilized SBS (0.3 or 0.4% of diet) or control diets using sodium sesquicarbonate (0.2 or 0.3% of diet) as a sodium source. In Trial 2, birds were challenged with a 2 × dose of coccidiosis vaccine on d 0. Growth performance was measured on d 0, 14, 28, and 42. Each trial was analyzed independently to yield results for non-challenged or coccidiosis-challenged conditions. All data were analyzed with means separation using a Duncan's test. SBS and control treatments with equivalent sodium contributions were also directly compared. Significance was accepted at P ≤ 0.05. On d 28, broilers fed 0.4% SBS weighed more (P < 0.05) than broilers from either control, regardless of challenge status. This effect was sustained in the challenged broilers at d 42 but was not different (P > 0.05) in non-challenged broilers. No differences (P > 0.05) in feed intake or mortality were observed in either trial. Birds fed 0.4% SBS had lower feed conversion than both control treatments for d 0-42, regardless of challenge status. Collectively, these results indicate that SBS promoted growth performance with and without a coccidiosis challenge more than that of sodium sesquicarbonate as a supplemental sodium source. Because experimental treatments were balanced for mineral content, it is possible the sulfate content of SBS influenced these results.

Effects of Dietary Inclusion of a Proprietary Combination of Quillaja saponaria and Yucca schidigera on Intestinal Permeability and Immune Response in Broiler Chickens during a Coccidia Challenge

This study assessed the impact of Magni-Phi Ultra (MPU) inclusion on intestinal integrity and immunity in broiler chickens challenged with coccidia during peak and recovery phases. A total of 128 male Ross 708 broiler chicks were randomly allotted to one of four treatment groups (four chicks/cage). Treatments included an uninfected control (UUC); a coccidial challenge (CC) infected control (IUC); a CC fed salinomycin at 66 ppm (SAL); and a CC fed Magni-Phi Ultra at 0.11 g/kg of diet (MPU). At 16 days post-hatch, all birds in the CC groups were orally gavaged with a 3× dose of a live coccidia vaccine. At 5 dpi, the birds fed MPU and SAL showed decreased plasma FITC-d, oocyte shedding, and lesion scores and higher BWG compared to the IUC birds (p < 0.05). Jejunum IL-17, IL-10, and IFN-ϒ mRNA expression was higher in the IUC compared to the UUC (p < 0.05) group at 5 dpi. At 12 dpi, the birds fed MPU or SAL had lower plasma FITC-d and jejunum IFN-ϒ and IL-10 mRNA expression compared to the IUC birds (p < 0.05). This study indicates that MPU supports intestinal integrity and mucosal immune responses during the peak and recovery phases of infection, which may lead to improved health and performance.

Organ growth and fermentation profiles of broilers differing in body growth rate

This study sought to determine the relationship among broiler performance, organ development, and indicators of microbiota colonization. A total of 1,200 two-day-old male Ross 308 broiler chicks, divided among 3 cohorts of equal size, were housed in battery cages, and allotted based on body weight. On study d 11, birds were weighed, and birds with BW gain within the 10th and 90th percentiles were assigned to the Slow and Fast groups, respectively. Birds (n = 30 for each group) selected on d 11 were provided water and a corn-soybean meal-based diet ad libitum while maintained individually through study d 25 (i.e., a 14-d growth period). Parameters regarding growth performance, organ and intestine weights and lengths, and intestinal volatile fatty acid concentrations were measured. All data were analyzed by one-way ANOVA using the Mixed procedure of SAS. Fast birds exhibited greater (P < 0.001) BW gain and feed intake than slow birds, but feed conversion ratio (FCR) did not differ (P = 0.19). Additionally, Slow birds had higher (P < 0.05) relative weights (% of BW) for nearly all organs on d 11 and 25, most notably the gizzard, proventriculus, pancreas, and liver. Conversely, intestinal sections were longer (P < 0.05) in the Fast birds. Measurement of gut histomorphology did not show any notable differences between growth rate groups in terms of villi height, crypt depth, or their ratio for either time-point (P > 0.05). In terms of volatile fatty acid concentrations of luminal contents, acetate concentrations were 10.2% higher (P < 0.001) in the ileum of the Slow birds compared with Fast birds on d 25. Overall, the findings suggest that total BW gain is influenced by the development of metabolically active organs, as supported by lower weight gain in Slow birds with relatively larger organ weights and shorter intestinal lengths than their Fast counterparts. The general lack of differences in fermentation end-product concentrations in luminal contents does not rule out influence of the microbiota on growth rate of broilers, which warrants further investigation.