Abstract:
Alternatives to antibiotics are constantly being studied and one such alternative is organic acids. Organic acids can lower the pH in the gastrointestinal tract (GIT) and the lowered pH renders the environment unfavourable to pathogenic bacteria, thus resulting in a healthier GIT. This can enhance nutrient digestion, absorption and utilisation, as well as enhanced growth and efficiency of the bird.
The main objective of this study was to assess the optimal drinking water pH for broilers and what effects it would exhibit on the GIT. The second part of this study was to compare water acidification and feed acidification, as well as a combination thereof.
Two different feeds and five different water pH levels were fed to 7200 Ross 308 broilers, randomly allocated to 120 pens, with 12 replicates per treatment and 60 birds per pen. Feed 1 was considered as ‘standard’ and feed 2 was considered as ‘acidified’, containing 0.3% FORMI® (ADDCON 40% formic acid product). The five water pH levels tested were 3.0, 3.8, 5.5, 6.5 and tap water (pH of 7.9). Broiler performance and pH in various GIT segments were measured weekly.
The standard feed performed better than the acidified feed, irrespective of water pH. Standard feed resulted in significantly greater bodyweight (BW) and European performance efficiency factor (PEF) at weekly weighing intervals from 7-35 days, as well as significantly lower feed intakes (FI) and feed conversion ratio (FCR).The different water pH levels used throughout the trial showed clear trends and significant differences amongst the various treatments, irrespective of the feed used. Any level of drinking water acidification proved better than no acidification, with significantly higher BW and PEF on majority of the recordings, as well as significantly lower FCR and FI. Water intake was significantly higher for a water pH of 3.8 when compared to a pH of 7.9. When comparing the different drinking water pH levels across the two feeds, broiler performance always favoured the standard feed. Mortality was not significantly different and GIT pH was highly variable, showing no clear trends.
This study suggests that feed acidification is not as effective as water acidification and that a lower drinking water pH can significantly improve economically important measurements, such as BW and FCR. It can also be concluded that the effects exhibited on the pH of various GIT segments cannot be predicted. Based on this study, there is no clear benefit to combining feed and water acidification and a drinking water pH of 3.0 – 3.8 is recommended.
