Efficiency of Weizmannia Faecalis in Improving Broiler Performance and Gut Health in Challenged Birds ^†

Abstract

The objective of the present study was to evaluate the probiotic impact of Weizmannia faecalis (formerly Bacillus coagulans) DSM 32016 on the performance parameters and intestinal health of broiler chickens reared under high stocking density and mild heat stress conditions. The trial involved 320 day-old ROSS broiler chicks, randomly assigned to two experimental groups (8 pens per group). The control group received a standard commercial diet while the experimental group was supplemented with W. faecalis. At 42 days of age, 24 birds from each group were slaughtered for carcass composition analysis and evaluation of the weight of individual cuts. Probiotic supplementation significantly increased final body weight and improved feed conversion ratio, resulting in a significant increase in drumstick weight and breast meat yield, while the average feeding cost per kg broiler decreased by 5%. Collectively, the probiotic diet supplementation enhanced growth performance, alleviating the adverse effects of high stocking density and thermal stress.

1. Introduction

In 2006, the EU banned the use of antibiotics as growth promoters in farm animals’ diets to reduce the emergence of microbial resistance to antibiotics [1]. This marked a turning point for the poultry industry since the use of growth promoters has improved broiler growth by 4–8% and feed utilization by 2–5%, and it has also reduced the incidence of subclinical intestinal infections [2]. Since then, several alternatives to antibiotics have been proposed, including, among others, prebiotics, organic acids, enzymes, and probiotics.

According to the FAO and WHO, probiotics are defined as “live micro-organisms which when administered in adequate amounts confer a health benefit on the host” [3]. In most cases, the term micro-organisms refer to bacteria (mainly belonging to the genera Lactobacillus, Bifidobacterium, Bacillus, and Enterococcus) but certain yeasts and fungal probiotics are also used, e.g., Aspergillus oryzae, Candida pintolopesii, Saccharomyces, and Saccharomyces cerevisiae.

The mode of action of probiotics is quite complex and multidimensional. It has been proven that probiotics enhance the multiplication of beneficial microbes and suppresses the harmful ones, thus changing the microbial population dynamics in the gastrointestinal track [4]. Moreover, experiments in broilers have shown that the dietary supplementation of poultry feed with probiotics increases the digestion and absorption of nutrients [5]. Other modes of action include effects on quorum sensing in pathogenic bacteria, thus influencing their pathogenicity [6]; the prevention of chronic inflammation of the gastrointestinal track through stimulation of innate immunity in the epithelium [7]; demonstration of immunostimulatory effects [8]; and prevention of pathogenic micro-organisms’ colonization of the intestinal mucosa [9].

Many studies have shown that adding probiotics to diets can improve growth performance, feed conversion ratio (FCR), and nutrient digestibility in broilers [10,11], but there have also been inconsistent field results that show the need for more detailed, strain-specific research and clearer guidelines for use. Probiotic strains of Weizmannia (formerly Bacillus) uniquely combine heat stability and homofermentative lactic acid production [12]. These properties contribute to their widespread use in supporting gut health in both humans and animals [13,14].

Taken altogether, the aim of this study was to evaluate the dietary impact of including Weizmannia faecalis (formerly Bacillus coagulans) DSM 32016 as a probiotic on performance and gut health under conditions of high stocking density, reused litter, and mild heat stress.

2. Materials and Methods

A total of 320 ROSS day-old broilers were purchased from a local hatchery and transferred, as hatched, to the experimental facilities of the Research Institute of Animal Science in Giannitsa, Greece. The facilities comprised solid floored pens (100 × 100 cm) with chopped wheat straw bedding. Upon arrival, the birds were individually weighed and randomly allocated to 2 treatments (160 birds per group; 8 pens per group, 20 birds per pen): control (C), wherein chicks were fed a standard commercial feed based on maize and soya-meal, and probiotic (P), wherein chicks were fed the control feed further supplemented with Weizmannia faecalis (formerly Bacillus coagulans) DSM 32016 as a probiotic. The feeding schedule was as follows: Starter, 1–10 days, mash; Grower, 11–24 days, mash; Finisher, 25–42, mash. Feed and water consumption were ad libitum. The composition and analysis of experimental diets are presented in

Table 1. Composition and calculated analysis of the control diet.

Ingredient (%)	Starter (1–10 d)	Grower (11–24 d)	Finisher (25–42 d)
Corn	42.9	48.5	52.1
Wheat	10.0	10.0	10.0
Soymeal 47%	33.6	30.2	22.6
Sunflowermeal 33.7%	4.5	4.0	4.0
Soy oil	3.3	4.2	4.8
Phytase	0.0	0.0	0.0
Choline 60%	0.1	0.1	0.1
Metheionine DL	0.2	0.2	0.2
Salt	0.3	0.2	0.3
Vit + minerals premix	0.2	0.2	0.2
Lysine	0.3	0.3	0.2
Threonine	0.1	0.1	0.1
Emulsifier	0.1	-	0.1
Phosphorus	1.1	0.9	0.6
Calcium	1.1	1.0	0.9
NaHCO3	0.1	0.1	0.1
Wheat bran	2.2	-	3.0
Soy protein 63%	-	-	1.0
Analysis (%)
Dry matter	87.9	87.9	87.8
Crude Protein	22.9	21.0	19.0
Fiber	3.2	3.1	3.1
Fat	5.0	6.5	7.3
Ash	5.6	5.1	4.4

.

Body weight (BW) and feed intake (FI) were recorded at the end of every feeding period (days 0, 10, 24, and 42) per pen. Mortality was recorded continuously until the end of the experiment. At 42 days, 3 birds per pen were slaughtered and all carcasses were scored for footpad lesions. Twenty-four hours after slaughter, the weights of cold carcass, thigh, drumstick, liver, abdominal fat, and carcass yield were also recorded. Finally, average daily gain (ADG), feed conversion ratio (FCR), and European Poultry Efficiency Factor (EPEF) were calculated based on the recorded data.

Data were analyzed using the STATGRAPHICS statistical software designed for Windows. Body weight, average daily gain, feed intake, feed conversion ratio, and the weights of carcasses and carcass parts were submitted to multifactor analysis of variance (ANOVA), treating the probiotic dietary supplementation (C vs. P) and age along with their interaction as fixed effects. Within treatments, data were checked for outliers, which were only rejected after examining plausibility. Pair wise comparisons were tested at 0.05 significance level with Tukey’s honest test, and the results are presented as least square means ± standard error of estimation (pooled SEM).

3. Results

Body weight (BW), average daily gain (ADG), feed intake (FI), and feed conversion ratio (FCR) of the experimental groups are presented in

Table 2. Body weight (BW), average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR) of the experimental groups per feeding period.

		C	P	SEM	Significance 1
DAY 10	BW (g)	299.6	301.5	3.7	ns
	ADG (g/d)	25.4	25.6	0.4	ns
	FI (g/bird)	370.9	375.1	2.5	ns
	FCR	1.24	1.24	0.01	ns
DAY 24	BW (g)	1106	1191	25	ns
	ADG (g/d)	57.6	63.5	1.6	*
	FI (g/bird)	1260	1303	33	ns
	FCR	1.58	1.47	0.05	ns
DAY 42	BW (g)	2575	2786	51	*
	ADG (g/d)	81.6	88.6	2.9	td
	FI (g/bird)	2809	2843	63	ns
	FCR	1.73	1.62	0.03	*

¹ Level of significance: ns—nonsignificant, td—p ≤ 0,10, * p ≤ 0.05.

. For BW, while no significant differences in age were recorded on D10 and D24, at D42, the probiotic treatment was heavier than the control group by more than 200 g (p ≤ 0.05). ADG was higher in the probiotic supplemented group than the control by more than 5 g/d, throughout the whole experimental duration. Feed intake was not different among groups at any stage of growth (p > 0.05). On the other hand, FCR was lower at D42 for the supplemented group (p ≤ 0.05), indicating that the probiotic supplementation significantly improved feed conversion.

Table 3. Carcass weights (% cold carcass weight), EPEF, and footpad scoring of the experimental groups.

	C	P	SEM	Significance 1,*
Abd. Fat	1.1	1.2	0.1	ns
Liver	3.2	2.6	0.1	**
Thigh	7.8	8.1	0.3	ns
Drumstick	5.9	6.4	0.1	***
Breast	41.4	39.6	0.4	**
EPEF	344	392	5.2	***
Footpad Scoring	2.1	1.9	0.2	ns

¹ Level of significance: ns-nonsignificant, * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001.

presents the carcass weights of the experimental groups after slaughter as proportions of the cold carcass weight. The abdominal fat and the thigh weights were not different between the two groups. On the contrary, liver and breast weights reduced and drumstick weight increased proportionally in the supplemented group (p ≤ 0.05). Moreover, the probiotic dietary supplementation improved the EPEF, while footpad scoring was not different between the groups.

In economic terms, the above-mentioned differences in BW and FI resulted in a 5% decrease in the average feeding cost per kg broiler produced, thus resulting in a 40% average increase in the gross net income per 1 thousand broilers if all the other cost components remain the same (heating costs, labor costs, etc.).

4. Discussion

The beneficial effects of the use of probiotics in poultry nutrition are well documented [15,16]. Similarly to our research, other authors also reported that there is an increase in body weight and body weight gain using probiotics in poultry diets [5,17], while feed intake, in most cases, is not affected [18,19]. These increases are generally attributed to the improvement of the digestibility of nutrients, especially crude protein [20]. While there have been researchers who stated that the use of probiotics did not have any beneficial effect on growth performance of broilers [21], recent studies like that by Sjofjan et al. [22] concluded that body weight and body weight gain are positively affected by the dietary supplementation, whereas feed conversion ratio and mortality are negatively affected, after performing a meta-analysis of 49 papers published in the years 2008–2020.

Feeding cost represents about 70% of the total cost of broiler production, and therefore, an improvement in feed conversion ratio, as seen in this study, could have important implications for the profitability of farms in general. As already mentioned by Dotas et al. [23], who performed a typology analysis of broiler farming in Epirus, farms which achieved better FCR had higher average gross revenue as well as higher average farm income and return on invested capital, the size of which depended on farm size and production cycles.

In conclusion, probiotics play a vital role in modern poultry nutrition, offering multifaceted benefits that align with consumer preferences, animal welfare, and public health goals. In this study, the W. faecalis DSM 32016 supplementation, under challenging rearing conditions, enhanced growth performance, alleviating the adverse effects of high stocking density, reused litter, and thermal stress. The continued innovation in probiotic delivery systems, coupled with precision nutrition approaches, is likely to enhance their effectiveness and adoption in the poultry industry in the future.