Limestone particle size (PS) affects its solubility and thus can influence broiler performance by altering the rate of calcium (Ca) release into the gastrointestinal tract. The objective of this research was to determine, using 2 × 2 × 2 factorial arrangement, the influence of PS (fine and coarse) and supplemented phytase (0 and 1,000 FYT/kg) in diets formulated with 2 Ca and Pi levels (positive control [PC]; negative control [NC]) on live performance, bone ash, and apparent ileal nutrients digestibility (AID). Starter PC: 0.9 Ca and 0.45 Pi; NC: 0.72 Ca and 0.03 Pi. Grower PC: 0.76 Ca and 0.38 Pi; NC: 0.58 Ca and 0.23 Pi. The 8 diets were assigned randomly to a total of 1,512 birds, with 21 birds per pen and 9 pens per treatment. The main effects of PS and Ca and Pi levels had no influence on feed intake (FI), body weight gain (BWG), or feed conversion ratio. Adding phytase improved BWG by 8 g and 50 g and FI by 25 g and 56 g at 0-14 D (P ≤ 0.05) and 0-35 D (P ≤ 0.05), respectively. Interaction between Ca and Pi levels and phytase improved BWG and FI for 0-14 D (P ≤ 0.05) and BWG during 15-28 D (P ≤ 0.05) for PC without phytase and for PC and NC with phytase when compared with NC without phytase. Birds fed PC without phytase, or either PC or NC with phytase were about 96 g heavier than NC without phytase. Birds fed either PC or NC diet with coarse limestone or PC with fine limestone gained approximately 14 g more (P ≤ 0.05) than birds fed NC with fine limestone for BWG at 0-14 D (P ≤ 0.05). Phytase increased tibia bone ash (14 D) by 1% (P ≤ 0.05). AID of Ca and Pi at 14 D was improved (P ≤ 0.05) by 66% when phytase was added to coarse limestone. Results indicate that phytase improved broiler performance without being affected by PS. Furthermore, phytase had greater influence on coarse limestone than on fine limestone for bone ash and AID. Ca and Pi levels were the most influential factors in determining bone ash although phytase inclusion could lead to an improvement during early days.

Carcass parameters and meat quality in lambs that consumed diets having layer hen litter (LL) were evaluated in a complete randomized study. Forty-two lambs were allocated equally (14 lambs/treatment diet) into one of three iso-nitrogenous diets for 75 days. To partially replace soybean meal and barley, LL was given at 0 (LL0), 150 (LL150), or 300 g/kg (LL300) of dietary dry matter (DM). At the termination of the trial, the characteristics of carcasses (hot and cold carcass weight, dressing percentage, and carcass cuts) and meat quality (Musculus longissimus linear dimensions, ultimate pH, cooking loss, water holding capacity (WHC), shear force (SF), color coordinates) were measured after slaughtering all lambs. Longissimus muscle weight was greatest (p < 0.05) for the LL150. For the dissected loin, intermuscular fat content was lowest for the LL0 diet. However, subcutaneous fat content was lower (p < 0.05) in the LL300 diet than LL0 and LL150 diets. Rib fat depth and Musculus longissimus area were greater (p < 0.05) for LL150 than L0. No differences were found in meat pH or color parameters among treatments but WHC and SF were lower in L0 lambs than in lambs fed LL containing diets. Cooking loss was greater for the LL300 diet than the LL0 diet. In summary, quality of meat and carcasses data indicate the possibility of inclusion of LL up to 300 g/kg DM to growing Awassi lambs.

The experiment investigated the effects of limestone particle size and dietary potassium (K) on live performance, blood physiology, and muscle myopathies in broilers raised to 35 days of age. A total of 384 Ross male broilers were placed in 24 floor pens and fed four diets during the starter (0–16 days of age) and grower (17–33 days of age) periods containing two limestone particle sizes (fine: 0.2 mm and coarse: 0.9 mm), and amended with either 0% basal K (K–) or 0.2% added dietary K (K+) as potassium carbonate to complete the 2 × 2 factorial arrangement. Live performance was measured from 1–33 days of age. Blood physiology, woody breast (WB), and white striping (WS) scores were measured at 35 days of age. The K+ dietary treatment reduced (P< 0.05) feed intake and BWG when compared to K– during the starter and grower period. The K+ dietary treatment decreased blood Na (mmol/L), blood glucose (mg/dl), ionized blood Ca (mg/dl), TCO₂(mmol/L), blood HCO₃(mmol/L), and base excess in extracellular fluid (mmol/L) when compared to K– birds of similar body weight at 35 days of age (P≤ 0.05). Fine limestone diets tended to reduce WB scores (3.0 vs. 2.59) when compared to coarse limestone diets at 35 days of age (P= 0.08). This study demonstrated that using 0.2% of K as potassium carbonate did not negatively affect FCR even though FI and BWG were reduced. Furthermore, fine limestone has the potential to reduce WB in breast muscle tissues; however, further research is needed to confirm these outcomes.

This study evaluated the inclusion of increasing levels of xylanase in reduced-energy diets for commercial laying hens. A total of 280 Lohmann LSL white laying hens were equally allocated one of five dietary treatments, with seven replicates of eight hens each being a positive control: a wheat and soybean meal-based diet (PC, ME 2725 kcal/kg), a negative control diet (NC, PC minus 100 kcal) and three diets with increasing xylanase levels of 50, 100 and 150 g/MT (NC + XM50, NC + XM100 and NC + XM150, respectively). The hens were monitored from 20 to 40 weeks of age to assess productive performance, egg quality and intestinal health, including histomorphometry, permeability and microbiota composition. Xylanase inclusion at 50 and 100 g/MT significantly improved egg production and egg mass, as well as shell strength and thickness, while maintaining feed intake and feed conversion efficiency, while xylanase inclusion at 150 g/MT decreased egg production and egg mass. Additionally, intestinal permeability was significantly reduced, and positive changes were observed in the gut microbiota. Higher doses of xylanase (100 and 150 g/MT) increased bacterial abundance and diversity, with a greater presence of beneficial phyla such as Bacteroidota, which play an important role in gut health. There was also a reduction in Actinobacteriota, indicating a lower presence of potential pathogens. Changes in Campylobacterota, Cyanobacteria and Proteobacteria were observed, especially with the highest xylanase dose. These findings suggest that xylanase can improve laying hen performance and promote intestinal integrity and microbial balance when included in energy-reduced diets, offering a promising strategy to enhance health and productivity in commercial egg production systems.

Organic acids are applied to poultry carcasses during processing to reduce foodborne pathogens and spoilage microorganisms. Scald water surfactant agents employed to improve feather removal may enhance the efficacy of organic acids during processing. This study investigated the effects of concurrent application of a scald water surfactant and organic acid dip on microbial contamination of carcasses processed in a small-scale production model. Broilers were reared in litter floor pens to 47 d of age and slaughtered using standard practices. Carcasses were scalded in either control or surfactant scald water initially and dipped in either a 2% organic acid blend or water after feather removal to complete a 2 pound 2 factorial arrangement with n = 15 carcasses per treatment group. The commercially available scald water additive was a slightly alkaline surfactant solution labelled as a feather removal aid. The organic acid dip consisting of lactic and citric acid was maintained at pH of 2.5. Approximately 10 g of neck skin was collected 1-min postdipping and placed in buffered peptone water with an added neutralizing agent, sodium thiosulfate. Serial dilutions were performed to determine general coliform (GC), E. coli (EC), and aerobic plate (APC) counts as CFU per gram of skin sample. A significant 0.61, 0.76, and 1.6 log reduction of GC, EC, and APC, respectively, was attributed to use of the organic acid carcass dip (P <= 0.01). There were no significant differences in carcass microbial reduction due to surfactant scald water alone. A 0.69, 0.73 (P P < 0.05), and 1.96 log reduction of GC, EC, and APC, respectively, was observed in surfactant-scalded, acid-dipped carcasses compared to water-scalded, water-dipped control groups. These data demonstrated that a surfactant scald water additive and an organic acid carcass dip can have beneficial effects of microbial reduction when employed simultaneously during broiler processing.