The Chinese researchers said they wanted to determine whether including natural capsaicin extract (NCE) in feed, as an alternative to the antibiotic chlortetracycline (CTC), would positively impact the birds’ growth performance, antioxidant capacity, immune function and meat quality.
They found broiler chickens fed NCE diets exhibited similar growth performance and health status to those fed CTC diets. “Therefore, NCE is considered as an effective alternative to AGP in broilers," remarked the team in an article published in Poultry Science.
Chili pepper (Capsicum annuum) is widely planted throughout the world, said the authors.
The researchers said capsaicin has been shown to play an important role in the improvement of antioxidant capacity and anti-inflammatory activity, relief of pain, and modulation of lipid metabolism and intestinal microbial community (Lee et al., 2003; Aasvang et al., 2008; Liang et al., 2013; Prakash and Srinivasan, 2010). Thus, they anticipated that natural capsicum extract (NCE) might positively affect poultry production.
In terms of the methodology of the study, the authors outlined how 168 one-day-old Arbor Acre male broilers were randomly allotted into three treatments, with seven replicates per treatment and eight broilers per cage.
The three dietary treatments were as follows: CON (corn-soybean meal basal diet), CTC (basal diet + 75 mg/kg chlortetracycline), and NCE (basal diet + 80 mg/kg NCE).
They study was conducted over two periods (day 1-21 and day 22-42), and two types of diets were formulated to meet nutrient levels recommended by National Research Council (NRC, 1994), explained the team.
The NCE used in the trial was supplied by Leader Bio-Technology Co., Ltd (Guangzhou, China), and the main bioactive compound of the NCE was natural capsaicin (2%). The chlortetracycline was purchased from Tonglixingke Agricultural and Technology Co., Ltd.
Broilers from the NCE group showed higher average daily gain (ADG) compared to broilers from the CON group at all stages, observed the team.
They also saw that, on day 42, NCE supplementation improved dietary nitrogen-corrected apparent metabolizable energy compared to non-supplemented or CTC-supplemented diets.
The digestibility of organic matter (OM) and crude protein (CP) were higher in the NCE diet than in the CON or CTC diets, said the authors.
Higher relative weight of bursa of Fabricius was observed in broilers fed NCE diets compared with CON, and pancreatic trypsin and lipase activities were significantly increased in the NCE group compared with those in the CON group.
The value of lightness of breast muscles from broilers fed NCE diets was significantly lower compared to those fed CON diets, they said.
Broilers fed NCE diets also had higher levels of serum total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and lower levels of interleukin-1β and tumor necrosis factor-α compared with broilers fed CON diets while the liver catalase activity of broilers was also significantly increased in the NCE group than the CON group, noted the team.
In addition, broilers from NCE group had lower concentrations of serum urea-N, low-density lipoprotein cholesterol, and total cholesterol, and higher concentration of growth hormone compared with those from the CON group, they reported.
“Therefore, we concluded that supplementation of 80 mg/kg of NCE in diets could improve growth performance, nutrient digestibility, antioxidant status, immune function, and meat quality in broilers.”
Mode of action
Discussing the reasons why the plant extract had such benefits, the authors cited corroborating findings from other work.
They noted that Atapattu and Belpagodagamage (2011) previously demonstrated that 5% of chili powder supplementation to broilers diets could significantly increase body weight at day 49 and ADG at day 30-49, while Pirgozliev et al. (2019) reported that 100 mg/kg of phytogenic feed additives with 2% of capsicum oleoresin could improve weight gain by 16.4%. Meanwhile, Liu et al. (2013) found that the addition of 10 mg/kg of capsicum oleoresin resulted in an enhanced growth performance of piglets challenged with F-18 E. coli, they said.
“Capsaicin has been proved to have antioxidant capacities and anti-inflammatory activities (Nascimento et al., 2013; Liu et al., 2012). In addition, it has been reported that capsaicin was beneficial to the gut health of animals (Liu et al., 2013). Vicente et al. (2007) showed that supplementing natural capsaicin to diets could significantly decrease the abundance of pathogenic bacteria in hens challenged by Salmonella enteritidis. Jamroz et al. (2003) also reported that 100 mg/kg of plant extract (including 1.98% capsaicin) could lower the abundance of E. coli and Clostridium perfringens in the rectum.
“At the same time, the enhanced growth hormone level was observed in broilers fed NCE diets in the current study, and the increase of GH concentration may be also one of the reasons for the improvement of growth performance in broilers fed NCE diets.
“Calcitonin gene-related peptide (CGRP) has been proved to promote the secretion of growth hormone in the body (Nakamura et al., 1998; Fahim et al., 1990). Studies showed that capsaicin could stimulate capsaicin-sensitive afferent neurons after entering the body, thus leading to the secretion of endogenous CGRP (Evangelista, 2009).”
In terms of CP, OM and dry matter (DM) digestibility, the researchers also cited work by Ilsley et al. (2003) showing that plant extract including capsaicin could improve CP digestibility of sows in the first week of lactation, and the addition of plant extract tended to increase DM and OM digestibility during this period.
The improvement in nutrient digestibility might be related to the increase of digestive enzyme activities, remarked the team.
Looking at the positive effects NCE had on the immune function of broilers, the researchers said the relative weight of the bursa of Fabricius in broilers fed NCE diets were higher than those of CON.
Tollba et al. (2007) also indicated that antioxidants (including capsaicin) supplementation of Egyptian chicken diets could increase the relative weight of the bursa of Fabricius, a key indicator of the health status of animals, according to Mahfuz et al., 2018, reported the team.
“The increase of the relative weight of the bursa of Fabricius demonstrated that NCE supplementation could efficiently improve some aspects of immune function in broilers.
“Furthermore, lower concentrations of TNF-α and IL-1β were observed in broilers fed NCE diets compared with broilers from the CON group, and these results showed that NCE could exert an anti-inflammatory effect in broilers.”
The authors also surmised the phenolic structure of capsaicin might be the reason why it exhibited antioxidant capacity.
Source: Poultry Science
Title: Effects of natural capsicum extract on growth performance, nutrient utilization, antioxidant status, immune function, and meat quality in broilers
Authors: SJ Liu, J Wang. TF He, HS Liu, XS Piao