Effect of Chromium Picolinate, Alone or in Combination with Vitamin C or Formic Acid on Growth, Carcass Traits, Immune and Blood Parameters of Broilers under Heat Stress

Faramin Javandel Soum Sarai1, Mir Daryoush Shakouri2* and Alireza Seidavi3*

1PhD Candidate, Department of Animal Science, University of Mohaghegh Ardabili, Ardabil, Iran

2Department of Animal Science, University of Mohaghegh Ardabili, Ardabil, Iran

3Department of Animal Science, Rasht Branch, Islamic Azad University, Rasht, Iran

ABSTRACT

The experiment was performed to evaluate the effect of chromium picolinate, alone or in combinationwith vitamin C or formic acid on performance, carcass traits and some blood biochemical and hematological parameters of broilers under heat stress (34 ˚C for 8 h). A total of 160 28-d-old Ross 308 broiler chickens were divided into 4 treatment groups with 4 replicates and 10 birds per each by employing a completely randomized design. Broilers were fed on corn-soybean meal basal diets with no additive (control) or added chromium picolinate (400 mg/kg), chromium picolinate (400 mg/kg)+ vitamin C (240 mg/kg) or chromium picolinate (400 mg/kg) +formic acid (0.5%) form 29 to 42 days of age. All supplements significantly improved daily feed intake, daily weight gain and feed conversion ratio of birds compared with the control (P<0.05). The treatments reduced the abdominal fat (P<0.05) and had no effect on the other carcass traits. Relative weight of immune organs was significantly increased by the dietary treatments (P<0.05). The supplements caused a significant increase in total protein and a decrease in glucose, total cholesterol, and LDL cholesterol concentrations (P<0.05). All supplements significantly decrease mean corpuscular volume (MCV), percentage of heterophils and the ratio of heterophil to lymphocyte (H/L), and increased mean corpuscular hemoglobin concentration (MCHC) and white blood cells (WBC) (P<0.05). Addition of formic acid lowered the effect of chromium picolinate on performance parameters, abdominal fat and spleen weights (P<0.05). The results suggest that supplemental chromium picolinate alleviate the adverse effects of heat stress. No synergistic effect was observed between vitamin C or formic acid with chromium picolinate, and in some cases formic acid exacerbated the effect of chromium picolinate.

Article Information

Received 05 June 2022

Revised 11 August 2022

Accepted 26 September 2022

Available online 28 December 2022

(early access)

Published 27 January 2024

Authors’ Contribution

FJS, MDS and AS presented the concept, wrote and edited the mauscript. FJS performed investigation and data collection. FJS, MDS and AS provided resources, and reviewed and edited the mauscript.

Key words

Heat stress, Formic acid, Vitamin C, Chromium picolinate, Broiler, Blood parameters

DOI: https://dx.doi.org/10.17582/journal.pjz/20220605060642

* Corresponding author: mdshakouri@uma.ac.ir, alirezaseidavi@iaurasht.ac.ir

0030-9923/2024/0002-0711 $ 9.00/0

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

Heat stress is one of the most important environmental stress inducing factors that challenge commercial broilersaround the world, especially in tropical and subtropical regions, due to the economic losses related to reduced production performance and increased mortality. There are scientific evidences for the destructive effects of heat stress on growth performance (Chougule et al., 2018), carcass characteristics (Huang et al., 2016), blood biochemical (Ding et al., 2020) and hematological parameters (Ribeiro et al., 2018).

It is well known that activation of the hypothalamus- pituitary-adrenal (HPA) axis during stress increases the level of corticosterone in blood plasma of the birds (Lu et al., 2019), which facilitates the increase of infections by suppressing the immune system (Hirakawa et al., 2020). Chromium plays an important role in increasing the metabolism of nutrients such as carbohydrates, lipids, proteins, and nucleic acids by activating the enzymes associated with their metabolic pathways (Haldar et al., 2009). In fact, the major physiological role of chromium is to improve glucose tolerance (Hamidi et al., 2016), which increases the susceptibility of tissue receptors to insulin (Ezzat et al., 2017). Corticosterone secretion reduces the sensitivity of body cells to insulin during the stress (Sirirat et al., 2012), and in this case chromium improves bird performance by lowering blood corticosterone concentrations (Toghyani et al., 2006; Dalólio et al., 2018). It is illustrated that heat stress increases the mobilization of chromium from tissues, increases urinary excretion, and reduces the retention of chromium, which results in a deficiency of chromium in the body (Sahin et al., 2002), thus, the need for chromium increases in such cases. Chromium picolinate is a combination of a low-toxicity trivalent form of chromium combined with picolonic acid (Hamidi et al., 2016). The use of chromium picolinate supplement as a nutritional strategy in the diet of broilers under heat stress can improve growth performance (Toghyani et al., 2006), and carcass yield (Sahin et al., 2003), reduce depot fat (Kulkarni et al., 2018), improve immune organ weights (Lu et al., 2019) and blood parameters (Toghyani et al., 2006).

Vitamin C (ascorbic acid) is an unnecessary vitamin in poultry diets; as birds have the enzyme gluconolactone oxidase in their kidneys, which synthesize vitamin C from glucose (Khan and Sardar, 2005). However, during heat stress the endogenous vitamin C is not sufficient to meet the needs of birds (Abidian and Khatoon, 2013). On the other hand, vitamin C existsin high concentration in immune cells, which undergoes a rapid depletion under stress (Sorice et al., 2014). Vitamin C is not a part of the metabolic pathways; however, it is an essential factor for many enzymatic reactions involved in collagen carnitine, catecholamine, and tyrosine biosynthesis (Shakeri et al., 2020). Supplementation of vitamin C in the diet of broilers under heat stress reduces the synthesis and secretion of corticosteroids and decreases the plasma corticosterone concentrations by inhibiting the key enzymes involved in the corticosterone biosynthesis pathway (21-hydroxylase and 11-β-hydroxylase). It has been reported that under stress conditions, vitamin C supplementation can increase productivity, immune response, resistancetodiseaseand viability of broiler chickens (Whitehead and Keller, 2003).

Methanoic acid, known as formic acid, is the simplest carboxylic acid. One of the main applications of formic acid is to add it to feeds due to antibacterial activity against pathogens (Milillo et al., 2011) to prevent their subsequent colony formation in the digestive system of birds (Ricke et al., 2020). Moreover, the positive effects of formic acid have been previously reported on broiler body weight gain (Panda et al., 2009), feed intake, and feed efficiency (Kim et al., 2015), depot fat (Panda et al., 2009), cellular and humoral immunity (Ragaa and Korany, 2016), relative weight of immune organs (Ghazalah et al., 2011), and mortality (Brzoska et al., 2013) under normal condition. However, based on our knowledge, there is limited information about the effect of supplemental formic acidon broiler performance under heat stress. Therefore, there is room to study whether dietary inclusion of chromium picolinate with an acifieror vitamin C can show any additive effect to eliminate the adverse effects of heat stress. Hence, the aim of the current study was to compare the influence of above mentioned additives on growth, immunity and blood parameters of broiler chickens under heat stress.

MATERIALS AND METHODS

For this experiment, a total of 160 one-day-old male broiler chicks (Ross 308) were obtained from a local hatchery and raised on deep litter pens until 28 days of age, then weighed and randomly assigned to 4 dietary treatments with 4 replicates and 10 birds each with similar group weights. The experimental treatments were (1) basal diet without any supplement (control), (2) basal diet + 400 mg/kg chromium picolinate, (3) basal diet + 400 mg/kg chromium picolinate + 240 mg/kg vitamin C, and (4) basal diet +400 mg/kg chromium picolinate + 0.5% formic acid. The basal diet based on corn and soybean meal was formulated to meet or exceed the nutrients requirements recommended by Ross 308 production manual for starter (1 to 14 days of age), grower (15 to 28 days of age), and finisher (29 to 42 days of age) periods (Table I). The birds in all experimental groups had free access to water and feed for 23 h per day. The room temperature on the first day was set at 32˚C and gradually decreased to approximately 22 ˚C and then remained constant until 28 days of age. For application of heat stress, during 29 to 42 days of age the room temperature was raised to 34˚C for 8 h every day. Feed intake and body weight gain of birds per each replicate were recorded through the expemerimental period and then feed conversion ratio was calculated. The study was approved by the Animal Ethics Committee of the University of Mohaghegh Ardabili.

At the end of the experiment, two birds per replicate, each with a body weight close to the average body weight of each replicate were slaughtered after 4 h starvation. The feather removal and cutting into different parts were then performed manually. The different parts included carcass, breast, thigh, wing, neck,internal organs (gizzard, liver, heart, pancreas, and abdominal fat), and lymphoid organs (the bursa of Fabricius, thymus, and spleen) were weighed with a 0.001 g precision digital scale and expressed as the percent of live body weight.

To measure the biochemical and hematological parameters of blood, the samples of about 5 ml were taken from wing vein of two birds of each replicate on day 42 of the experiment. The samples were then poured into two test tubes. One tube containing EDTA anticoagulant was used to measure haemoglobin (Hb), red blood cells (RBC), white blood cells (WBC), and packed cell volume (PCV). RBC and WBC were counted using NAT solution by a hemocytometer. Hb and PCV levels were measured using cyanmethemoglobin and microhematocrit methods, respectively. Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) were estimated using the following common methods:

MCV (fL) = PCV × ×1000 / RBC

MCH (pg) = Hb×10 / RBC

MCHC (mmol/l or %) = Hb / PCV

Table I. Ingredients and chemical composition of the basal diets (%).

Ingredient	Starter	Grower	Finisher
Corn	54.32	60	64
Soybean meal	39.43	31.87	27
Corn oil	2.16	4.5	5
Oyster shell	0.90	0.97	1
Dicalcium phosphate	2.05	1.68	1.85
Common salt	0.37	0.37	0.35
Vitamin premix1	0.25	0.25	0.25
Mineral premix2	0.25	0.25	0.25
DL-methionine	0.20	0.22	0.18
L-lysine HCl	0.07	0.05	0.12
Chemical composition (calculated)
Metabolic energy (kcal/kg)	2900	3200	3220
Crude protein (%)	22.16	21.30	19.5
Calcium (%)	1	0.85	1.03
Available phosphorus (%)	0.50	0.42	0.58
Lysine (%)	1.15	0.96	1.12
Methionine (%)	0.50	0.48	0.49
Methionine + cysteine (%)	0.83	078	0.73
Threonine (%)	0.79	0.71	0.65

1Supplied per kg of diet: 3600000 IU vitamin A, 800000 IUvitamin D3, 7200 IU vitamin E, 710 mg vitamin B1, 2640 mg vitamin B2, 1176 mg vitamin B6, 400 mg vitamin B9, 6 mg vitamin B12, 800 mg vitamin K3, 3920 mg pantothenic acid, 12,000 mg niacin, 40 mg biotin and 200,000 mg choline chloride. 2Supplied per kg of diet: 40,000 mg manganese,20,000 mg iron, 33,900 mg zinc, 4,000 mg copper, 400 mg iodine, and 80 mg selenium.

The blood serum was used to measure blood biochemical parameters including total protein, albumin, glucose, cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, and uric acid. Blood biochemical parameters were measured using the enzymatic method with Randox-Ransod commercial kits and auto-analyzer spectrophotometer. The levels of triiodothyronine (T3) and thyroxine (T4) were measured using ELISA kits, according to the recommended instructions, with the help of an ELISA reader device.

The collected data were statistically analyzed using the General Linear Model procedure of SAS software. Duncan’s multiple range test was used to compare the significant difference (P<0.05) between the means. The statistical model of the design was as follows:

Yij= µ +Ti + Eij

Where Yij represents each observation in the experiment, µ indicates the total mean, Ti represents the effect of the i-th experimental treatment, and Eij represents the experimental error.

RESULTS

Performance

The effect of chromium picolinate with or without formic acid and vitamin C on birds growth performance during heat stress (29 to 42 days of age), and the whole experimental (0 to 42 days of age) periods are presented in Table II. The chickens consuming the chromium picolinate supplement alone or in combination with either vitamin C or formic acid had significantly (P<0.05) higher daily weight gain and feed intake compared with the control group. The birds on chromium picolinate plus vitamin C had similar daily weight gain and feed intake with those on chromium picolinate alone, whereas the chickens fed with formic acid and chromium picolinate had significantly (P<0.05) lower daily weight gain and feed intake than those receiving chromium picolinate alone. Moreover, the chickens fed with chromium picolinate alone or in combination with vitamin C showed the best feed conversion ratio and was followed by the group on chromium picolinate and formic acid (P<0.05).

Carcass characteristics

As shown in Table III, supplementation of different dietary treatments had no significant effect on relative weights of carcass, breast, thigh, wing, neck, gizzard, liver, heart, and pancreas compared with the control. However, all treatments significantly (P<0.05) decreased relative weight of abdominalfat of the birds. The effect was more pronounced by chromium picolinate alone or in combination with vitamin C.

Immune organs

Table IV shows the effect of the supplements on immune organ weights (the bursa of Fabricius, thymus, and spleen) of birds at 42 days of age. All supplements significantly (P<0.05) increased the relative weights of bursa of Fabricius and thymus in comparison with the control.The relative weight of spleen was also significantly (P<0.05) increased by the treatments and the birds on chromium picolinate alone or in combination with vitamin C had the heaviest spleen.

Table II. The effects of dietary treatments on boriler chickens growth performance under heat stress during the experimental periods.

Parameters	Treatments				SEM	P-value
Parameters	Control	Chromium	Chromium+ Vitamin C	Chromium + Formic acid	SEM	P-value
0-28 d
Daily weight gain (g)	40.26	40.21	40.33	40.18	0.146	0.989
Daily feed intake(g)	62.50	62.26	62.61a	62.31	1.143	0.846
FCR	1.553	1.548	1.552	1.552	0.007	0.997
29-42 d
Daily weight gain (g)	72.64c	83.21a	83.62a	77.73b	0.590	<0.001
Daily feed intake (g)	147.78c	157.78a	157.95a	153.07b	1.267	<0.001
Feed conversion ratio	2.09a	1.896c	1.890c	1.970b	0.249	<0.001
0-42 d
Daily weight gain (g)	50.39c	54.54a	54.76a	52.70b	0.543	<0.001
Daily feed intake(g)	90.93c	94.10a	94.40a	92.56b	0.426	<0.001
Feed conversion ratio	1.804a	1.725c	1.723c	1.756b	0.010	<0.001