Superdosing phytase reduces real-time gastric pH in broilers and weaned piglets

Abstract

1. The current study was conducted to investigate the effect of high phytase doses on growth performance and real-time gastric pH measurements in broiler chickens and pigs. 2. In the first experiment, 576 male Ross 308 broilers were fed in two phases (0-21 and 21-42 d) with 4 treatment groups, with diets meeting nutrient requirements containing 0, 500, 1500 or 2500 FTU/kg phytase. In the second, 64 Landrace weaners were fed on diets meeting nutrient requirements with or without phytase (0 or 2500 FTU/kg) in two phases (0-21 and 21-42 d). Heidelberg pH capsules were administered to 7 broilers and approximately 13 pigs per treatment group, pre- and post-phase change, with readings monitored over several hours. 3. Addition of phytase into an adequate Ca and P diet had no significant effect on broiler performance although phytase tended (P < 0.07) to improve feed conversion in pigs over the entire experimental period. Real-time pH capsule readings in broilers demonstrated an increase (P < 0.05) in gizzard pH when phytase was dosed at 500 or 1500 FTU/kg, while higher doses of 2500 FTU/kg phytase lowered pH to a level comparable to control birds. Gastric pH increased (P < 0.01) when animals were exposed to dietary phase change, signifying a potential challenge period for nutrient digestibility. However, pigs fed 2500 FTU/kg were able to maintain gastric pH levels through diet phase change. In contrast, spear-tip probe measurements showed no treatment effect on gastric pH. 4. These findings demonstrate dietary manipulation of gastric pH and the value of real-time pH capsule technology as a means of determining phytase dose response.

Application of Creep Feed and Phytase Super-Dosing as Tools to Support Digestive Adaption and Feed Efficiency in Piglets at Weaning

“…Isolation of digesta from the tract prior to taking pH measurements has been shown to interfere with pH determinations [40] due to a change in environmental conditions. In addition, pH measurements taken in situ have shown higher variability and lack of treatment effect compared to real-time measurements in the live animal [26], suggesting that point-in-time measurements are not representative of gastric pH fluidity. With age and an increase in solid feed, chymosin is gradually substituted by pepsin [41], and as such, a lowering of stomach pH by HCl secretions is necessary to achieve optimal digestive function.…”

“…Although changes to stomach function have been less studied in comparison to the intestine at weaning, gastric efficiency is crucial for overall digestive success. In a previous study using real-time pH capsules [26], pigs fed diets supplemented with 2500 FTU/kg phytase were able to maintain stomach pH through a potentially challenging period associated diet phase change. Therefore, it is possible that both creep and phytase could regulate stomach pH during weaning, and as a result, support feed efficiency in the young pig.…”

Genome-Wide Identification of Genes Involved in Acid Stress Resistance of Salmonella Derby

“…More than 80 strains were then selected to determine the virulence of the S. Derby, and 14T-T8N3 (14T-herein), a strain affiliated with ST40, the most prevalent ST type as revealed by our previous epidemiological investigation [6], exhibited the highest virulence. Here, we determined S. Derby 14T's growth ability under different pH conditions, and demonstrated that pH4, similar to the acidic environment in the pig stomach after eating [28][29][30], delayed the growth rate but not the maximum biomass of S. Derby 14T. We then generated a high-quality genome assembly of 14T using a de novo long-and short-reads hybrid assembly approach, and used this to identify the essential acid stress genes of S. Derby 14T by Tn-seq.…”

“…However, the WT cultured in pH 4.0 exhibited a significantly delayed growth rate, but reached a similar maximum biomass to the pH 7.0 condition (Figure 2A). Interestingly, pH 4.0 represents the actual stomach acidity of pigs after eating [28][29][30]. Therefore, we constructed a high-throughput Tn5-based mutant library of S. Derby 14T, and determined the genes involved in acid stress resistance by Tn-seq analysis to identify the genes responsible for acid resistance (pH 4.0).…”

Effects of supplementation of high‐dosing Trichoderma reesei phytase in the corn‐wheat‐soybean meal‐based diets on growth performance, nutrient digestibility, carcass traits, faecal gas emission, and meat quality in growing‐finishing pigs

“…Secondly, limestone is the dominant source of Ca in the diet of pigs, and it has an extremely high acid buffering capacity (Selle et al, 2009); therefore, dietary supplementation of limestone makes stomach pH elevated to adverse effects on the phytase activity. Commonly, the stomach pH was shown to range between 0.79 and 3.64 in pigs (Lee et al, 2018). When pigs have free access to feed, the stomach pH is shown to range from 3.8 to 4.6 (van Winsen et al, 2001).…”