Effects of protease supplementation of low protein and/or energy diets on growth performance and blood parameters in broiler chickens under heat stress condition

Abstract

The effects of feeding low dietary crude protein (CP) and/or metabolisable energy (ME) with or without supplemental protease on growth performance, carcase characteristics and physiological responses in broiler chickens were investigated under cyclic heat stress condition. A total of 350 day-old male broiler chicks were fed with one of the following seven experimental diets: (1) recommended-CP and recommended-ME (RPE, served as control); (2) recommended-CP and low-ME (RPLE); (3) recommended-CP and low-ME with protease (RPLEP); (4) low-CP and recommended-ME (LPRE); (5) low-CP and recommended-ME with protease (LPREP); (6) low-CP and low-ME (LPE) and (7) low-CP and low-ME with protease (LPEP). From 22 to 42 d of age, half of the chickens from each dietary group were exposed to 34 ± 1 C for 7 h daily (heat stress), whereas the other half were raised at constant 23 ± 2 C (normal temperature). Supplementation of protease to RPLE, LPRE and LPE diets had no significant effects on feed intake (FI), weight gain (WG) or feed conversion ratio (FCR). Diet had no effect on serum glucose, total protein, certain acute phase proteins (APPs), corticosterone or breast yield. Regardless of protease supplementation, heat stressed birds had significantly lower FI, WG and breast yield, and higher FCR, APPs and corticosterone compared to birds raised in normal temperature. In conclusion, dietary supplementation of protease to low CP and/or ME diets showed negligible effects on growth performance, carcase characteristic and physiological responses in broiler chickens under heat stress condition. The inclusion of microbial protease in broiler diets could be considered by poultry industry as an effective nutritional tool for reducing ME or CP, in order to decrease abdominal fat deposition, improve feed efficiency and increase the profit margin. HIGHLIGHTS Protease supplementation has no specific help for broilers under heat stress. Feeding low CP and/or ME diet is not stressful for broiler chickens.

Effect of supplemental serine-protease from Bacillus licheniformis on growth performance and physiological change of broiler chickens

“…Previous experiments conducted on serine protease and threonine and found there benefit on growth performance (Cowieson andRavindran 2008 Ayaşan et al 2009;Angel et al 2011;Fru-Nji et al 2011;Vieira et al 2013;Okan 2014a, 2014b;Ding et al 2016;Lin-Law et al 2019;Ndazigaruye et al 2019) and. In addition, it was reported that supplemental protease reduced nitrogen excretion (Aletor et al 2000;Bregendahl et al 2002;Canogullari et al 2009) and decreased feed costs, and consequently broiler industry's production.…”

A review of heat stress in chickens. Part II: Insights into protein and energy utilization and feeding

“…So, in an effort to reduce the energy released during digestion, absorption, and metabolism of nutrients, dietary CP reductions have been proposed as a strategy to mitigate the harmful effects of HS in poultry ( Furlan et al, 2004 ). Numerous studies in broilers have tested the effects of feeding a reduced CP diet versus a standard CP diet under constant HS ( Alleman and Leclercq, 1997 ; Cheng et al, 1999 ; Faria Filho et al, 2005 ; Gonzalez-Esquerra and Leeson, 2005 ; Awad et al, 2018 ), cyclic HS ( Cheng et al, 1999 ; Liu et al, 2016 ; Awad et al, 2018 ; Zulkifli et al, 2018 ; Amiri et al, 2019 ; Lin Law et al, 2019 ; Soares et al, 2020 ) and hot climates ( Zaman et al, 2008 ; Laudadio et al, 2012 ; Awad et al, 2014 , 2015 , 2017 ; Lin Law et al, 2019 ; Attia et al, 2020 ). Table 1 summarizes 21 HS broiler trials comparing reduced CP diets (ranging from 143 to 190 g/kg CP) and standard CP diets (ranging from 183 to 223 g/kg CP), with both diets in each study formulated to meet or exceed a specific nutritional requirement, such as the Nutrient Requirements of Poultry ( NRC, 1994 ) or breeder recommendations, or to contain similar AA profiles.…”

Multienzyme Super-Dosing in Broiler Chicken Diets: The Implications for Gut Morphology, Microbial Profile, Nutrient Digestibility, and Bone Mineralization

“…Research has demonstrated that the addition of exogenous protease was able to modify the gut morphology, such as increasing villus length and supplementing the lack of endogenous enzyme secretion [8]. In addition, the addition of exogenous protease allows for a reduction in the amount of diet crude protein with no adverse effect on the feed intake, weight gain, and survivability rates in broilers [9].…”