Abstract: In order to study the efficacy of Yanning C1 in improving the production performance of commercial broiler chickens. Select 200 healthy 1-day-old AA broiler chickens with similar body weight and randomly divide them into 2 treatments, with 5 replicates per treatment and 20 chickens per replicate (see Table 1). Treatment 1: Control group, broiler chickens were fed a regular diet (NRC recommended nutritional level) without adding any antibiotics to the diet; Treatment 2 supplemented with Yanning C1:250 mg/kg on the same diet as Treatment 1. The experiment is divided into two stages (0-21d; 22-42d). Experimental chicken cage feeding, feeding pellet feed, with consistent dietary composition and nutritional levels between treatments. At 21 and 42 days, 10 chickens were randomly selected from each treatment (2 chickens per replicate) for slaughter experiments to determine slaughter performance. The measurement results indicate that:

Production performance and European index: Compared with the control group, the addition of Yanning C1 had no significant effect on the production performance indicators in the early stage (1-21d), late stage (22-42d), and whole period (1-21d), as well as the European index (P>0.05). Comparing and analyzing numerically, with the production performance indicators of the control group at 100%, after adding Yanning C1, the ADFI, ADG, and feed to weight ratio of commercial broiler chickens in the early stage (1-21d) were 101.1%, 103.9%, and 96.9%, respectively; The ADFI, ADG, and feed to weight ratio of commercial broiler chickens in the later stage (22-42d) were 96.2%, 102.4%, and 93.8%, respectively; The total period (1-42 days) was 97.5%, 102.9%, and 94.8%, respectively; At the same time, the body weight at 21 and 42 days was 103.7% and 102.8%, respectively, and the survival rate and European index increased by 4.8% and 13.8%, respectively.

Slaughtering performance: Compared with the control group, the addition of Yanning C1 significantly increased the spleen index at 42 days (P<0.05), significantly reduced the thymus index (P<0.05), 21="" and="" had="" no="" significant="" effect="" on="" all="" indicators="" at="" days="" p="">0.05). Comparing and analyzing numerically, with the meat production performance indicators of the control group at 100%, the addition of Yanning C1 increased the chest muscle rate, leg muscle rate, and thymus index by 6.0%, 3.4%, and 5.6% respectively after 21 days, decreased the spleen index by 10.0%, and increased the spleen index by 11.3% after 42 days.

Keywords: commodity broiler, Yanning C, production performance, slaughter performance

1. Materials and Methods

1.1 Test Materials

Yanning C1: A digestive stress additive formula mainly composed of complex enzymes. Provided by SD BIOTECH GROUP.

1.2 Experimental animals and design

Select 200 healthy 1-day-old AA broiler chickens with similar body weight and randomly divide them into 2 treatments, with 5 replicates per treatment and 20 chickens per replicate (see Table 1). Treatment 1: Control group, broiler chickens were fed a regular diet (NRC recommended nutritional level) without adding any antibiotics to the diet; Treatment 2 supplemented with Yanning C1:250 mg/kg on the same diet as Treatment 1. The experiment is divided into two stages (0-21d; 22-42d).

1.3 Experimental diet

Conventional diet for commercial broiler chickens in Shandong Province (see Table 2).

1.4 Test Method

Feeding experiment: The experiment is divided into two stages: broiler chickens (0-21d) and broiler chickens (22-42d). Experimental chicken cage feeding with powdered feed.

Slaughter experiment: 10 chickens were randomly selected for each treatment (2 chickens/replicate) at 21 and 42 days. Conduct slaughter experiments.

1.5 Measurement indicators

Production performance: Record feed intake daily and weigh at 21 and 42 days. Calculate the average daily feed intake, average daily weight gain, and feed to gain ratio. Record mortality rate, diarrhea rate, stool characteristics, mental state, etc. Calculate the European index.

Meat production performance: At 21 and 42 days, 10 chickens were slaughtered for each treatment, and the meat production performance (such as net bore rate, semi net bore rate, leg muscle rate, chest muscle rate, etc.) was measured.

Immune organ index: At 21 and 42 days, 10 chickens were slaughtered for each treatment, and their spleens and thymus were collected to calculate the spleen and thymus indices.

1.6 Data statistics and analysis

The data was analyzed using SAS 9.2 software, and Duncan's multiple range test was used to compare the mean values, with a significance level of p<0.05.

2. Results and Analysis

2.1 Comparative analysis of production performance

The effect of supplementing with Yanning C1250 mg/kg in the diet of commercial broiler chickens on production performance is shown in Table 3. Analysis of variance showed that compared with the control group, the addition of Yanning C1 had no significant effect on various indicators of production performance in the early stage (1-21d), late stage (22-42d), and whole period (1-21d) (P>0.05). Comparing and analyzing numerically, with the production performance indicators of the control group at 100%, after adding Yanning C1, the ADFI, ADG, and feed to weight ratio of commercial broiler chickens in the early stage (1-21d) were 101.1%, 103.9%, and 96.9%, respectively; The ADFI, ADG, and feed to weight ratio of commercial broiler chickens in the later stage (22-42d) were 96.2%, 102.4%, and 93.8%, respectively; The total period (1-42 days) was 97.5%, 102.9%, and 94.8%, respectively; At the same time, the weight at 21 days and 42 days was 103.7% and 102.8%, respectively.

2.2 European Index

The effects of supplementing 250 mg/kg of Yanning C1 in the diet of commercial broiler chickens on survival rate and European index are shown in Table 4. Analysis of variance showed that the addition of Yanning C1 had no significant effect on survival rate and European index (P>0.05). Comparing and analyzing numerically, with the control group's various indicators set at 100%, the addition of Yanning C1 increased the survival rate and European index by 4.8% and 13.8%, respectively, achieving good profitability indicators.

2.3 Comparative analysis of meat production performance

The effect of supplementing 250 mg/kg of Yanning C1 in the diet of commercial broiler chickens on production performance is shown in Tables 5 and 6. Analysis of variance showed that compared with the control group, the addition of Yanning C1 significantly increased the spleen index at 42 days (P<0.05), significantly reduced the thymus index (P<0.05), 21="" and="" had="" no="" significant="" effect="" on="" all="" indicators="" at="" days="" p="">0.05). Comparing and analyzing numerically, with the meat production performance indicators of the control group at 100%, the addition of Yanning C1 increased the chest muscle rate, leg muscle rate, and thymus index by 6.0%, 3.4%, and 5.6% respectively after 21 days, decreased the spleen index by 10.0%, and increased the spleen index by 11.3% after 42 days.

3. Conclusion

Compared to the control group:

3.1 Adding Yanning C1 to commercial broiler chickens can significantly reduce feed to weight ratio, improve feed efficiency, and reduce feed to weight ratio by 3.1%, 6.2%, and 5.2% in the early, late, and full stages, respectively; At the same time, the slaughter weight of broiler chickens increased by 3.7% and 2.8% at 21 and 42 days, respectively. The survival rate and European index increased by 4.8% and 13.8%, respectively, improving production performance and breeding income.

Adding Yanning C1 to commercial broiler chickens resulted in good chest muscle rate, leg muscle rate, and thymus index at 21 days, and significantly increased spleen index at 42 days. The chest muscle rate, leg muscle rate, and thymus index increased by 6.0%, 3.4%, and 5.6% respectively after 21 days, and the spleen index increased by 11.3% after 42 days.

Table 1 Experimental Design

Table 2 Experimental Diet Composition and Nutritional Level

Table 3: Effects of Yanning C on the Production Performance of Commercial Broiler Chickens

Table 4: The Effect of Yanning C on the European Index of Commercial Broiler Chickens

Table 5 Effect of Yanning C on the 21 day meat production performance of commercial broiler chickens

Table 6 Effect of Yanning C on 42 day meat production performance of commercial broiler chickens