New technologies improve feed efficiency New monitoring and modelling tools have enabled precision feeding systems for poultry to be developed that aim to feed birds individually according to measured body weight, on the one hand, and target weight, on the other. The quantity and quality of feeds (energy and amino acid levels) can then be adjusted in real time. Despite the fact that such systems have shown benefits in the experimental stage, their on-farm ap- plication has so far been limited for practical reasons: difficul- ty in adjusting the systems to various, non-standard commer- cial operations, sensitivity of the system, maintenance constraints, etc. More common practices are therefore being implemented in the field today, such as multiphase feeding or reducing the crude protein level in the diet while ensuring that it is still balanced in essential amino acids. Several stud- ies show promising results, although the impact of feeding a low protein diet still needs to be investigated.
Additives to reduce nitrogen excretion Meanwhile, new technologies are not exclusive to the digital world. Another means to reduce undigested feed and ammo- nia emissions is to support digestibility with in-feed solutions. Several types of feed additives are available on the market. Among them, an innovative product combining clay and macroalgae is very promising for its capacity to improve the efficiency of different types of diets, by increasing the activity of the digestive enzymes found in the gut. A series of studies was conducted by Pr Rostagno and Pr Albino at the University of Viçosa (Brazil) to evaluate the capacity of this algoclay complex (ACC) to improve the feed efficiency of broilers. One of the experiments evaluated the nitrogen-corrected appar- ent metabolisable energy (AMEn) of the diet of broilers fed with or without the ACC. The results showed that the use of the ACC increased the AMEn by 56 kcal/kg (+2% compared to the control). Measurements of nitrogen balance also showed that the ACC increased nitrogen retention by 6% (reflecting an improved use of proteins) and decreased nitrogen excre- tion by 8%, making it a good candidate for reducing poultry environmental impact. Other experiments focused on broiler performance. Three experiments were set up during 2018 and 2019, each differing in their supplementation of exoge- nous enzymes and with two treatment groups: a control (with no ACC supplementation) and a test (with 0.1% ACC supplementation in all feeding phases) (Table 1). The results of the three experiments were consistent, show- ing a lower feed conversion ratio in the test group compared to the control group (2-3% decrease, Figure 1), as well as a higher growth rate in the groups supplemented with the ACC compared to the control (2-4% higher ADG, Figure 2), inde- pendently of the use of exogenous enzymes. Interestingly, the greatest effect of the ACC on performance was observed in the grower and finisher phases (21-42 days), considered to be the most important in terms of economic and environ-
mental impact (>75% of the feed intake of broilers takes place after 21 days).
Net benefit Economically speaking, the improvement in performance in- creased the net benefit over feed cost from US$ 0.03 to US$ 0.08 per broiler in the test groups compared to the con- trol, with the highest savings made in study 3. All in all, this series of studies highlighted the capacity of the ACC to im- prove the feed efficiency and growth performance of broiler chickens, independently of the use of exogenous enzymes. Demonstration of a synergistic effect between the ACC and exogenous enzymes requires further investigation. Mean- while, the supplementation of broiler diets with the ACC, as part of a global strategy to reduce feed waste and environ- mental impact, has proven interest.
1.6 > Feed Conversion Ratio
-3%* 1.5 1.4 1.3 1.2 1.1 1.0 Study 1 Study 2
> Average Daily Gain (g/d)
50 55 60 65 70 75 80 85 90
+2% 80.3 78.4 +2.5% 70.0 68.3 77.3 +4%** 80.5 Study 3 1.490 1.446 1.488 1.455 -2%* 1.497 1.457 -3%*
Study 1
Study 2 ▶ POULTRY WORLD | No. 8, 2020 41
Study 3
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