In this study 288 broilers were used in a factorial 2 x 2 (completely randomized) design with 9 replicates of eight birds each. The broilers were fed a control diet (22% crude protein) or high protein diet (30%) with or without the supplementation of 0.5 kg/t protease (CIBENZA DP100, Novus International Inc.). All diets contained rye and wheat and the animals were subject to a coccidiosis challenge (subclinical enteritis model). Evaluations were done on ileal clostridium perfringens counts (15 days old) as well as on intestinal histology (14 days), the serum glycoprotein alpha 1-acid as an indicator of immune function (22 days), and the broilers performance (28 days).

In the second trial, three diets were fed (C) control, (BPAA) low crude protein and amino (-7%) and protease BPAA + Cibenza DP100. The animals were subjected to two rearing management regimes:

• (Normal) standard placing density and feeding conditions
• (Stress) high placing density and 8 hours of darkness

The performance parameters were evaluated at specific times, and the data was analyzed using procedures suitable for a randomized block design of the SAS® statistical program. The four diets with reduced protein were also analyzed in a factorial arrangement to evaluate the effect of stress, and the interaction between protease factors.

Results and Discussion

Study 1: In the absence of protease, increased protein in the diet increased (P <0.05) the Clostridium perfringen counts by 2 logs in the ileum (2.35 vs 4.34) (Figure 1).

The protease treated birds also showed improved intestinal health and reduction of systemic inflammation by improvement in the crypt to villus ratio (Figure 2) and lower serum glycoprotein alpha 1-acid, respectively.

Study 2: The inclusion of protease improved feed conversion throughout the experiment and especially under stress conditions between 0 to 14 days old (Table 3).

Conclusion

Some protein in the diet is not digested in the gut, either due to excessive supply of crude protein in the diet or by reduced intestinal function caused by stress conditions. This can lead to Dysbacteriosis, promoting the growth of Clostridium perfringens and reducing the performance.

The protease can alleviate these negative effects in young chickens by improving the digestion of protein.

* Note: Text adapted from the article “Effect of dietary protein and protease supplementation on performance and gut health of broiler chicks.“