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Han, C., Zhu,X., Chen, K., Wang, X., Leng, F., Wang, Y., and Li, S. (2024). “Comparative production performance and rumen bacterial diversity of fattening beef cattle supplemented with different levels concentrated feed,” BioResources 19(2), 2216-2243.

Abstract

The production performance and rumen bacterial diversity were compared for different silage-based diets supplemented with common concentrate or bio-concentrate to develop an alternative of common concentrate for fatten cattle feeding. The daily gain of fattening cattle was increased by 0. 99 kg and 1.04 kg, respectively, when fed with single corn silage or mixed silage-based diet supplemented with bio-concentrate. There was no significant difference in water loss rate and cooked meat rate among groups (P>0.05), but the tenderness of beef in the bio-concentrate group was significantly higher than that in the common concentrate group (P<0.05). There were no adverse effects on beef quality and blood biochemical indexes in each group. Compared with the normal concentrate group, the OTU number and α-diversity index of rumen microorganisms of fattening cattle fed with mixed silage as the basic diet supplemented with bio-concentrate increased significantly. At generic level, the relative abundances of Prevotella, Porphyromonadaceae (unclassified), and Succiniclasticum were increased by adding bio-concentrate in the diets based on mixed silage and single sorghum silage. Relative abundances of Bacteroidetes (unclassified), Ruminococcaceae (unclassified), and Firmicutes (unclassified) decreased. In conclusion, the bio-concentrate might be a better choice than common concentrate for beef cattle breeding.


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Comparative Production Performance and Rumen Bacterial Diversity of Fattening Beef Cattle Supplemented with Different Levels Concentrated Feed

Changze Han,a,b, § Xinqiang Zhu,a, § Kai Chen,b Xiaoli Wang,a,* Feifan Leng,b Yonggang Wang,b and Shaowei Li c

The production performance and rumen bacterial diversity were compared for different silage-based diets supplemented with common concentrate or bio-concentrate to develop an alternative of common concentrate for fatten cattle feeding. The daily gain of fattening cattle was increased by 0. 99 kg and 1.04 kg, respectively, when fed with single corn silage or mixed silage-based diet supplemented with bio-concentrate. There was no significant difference in water loss rate and cooked meat rate among groups (P>0.05), but the tenderness of beef in the bio-concentrate group was significantly higher than that in the common concentrate group (P<0.05). There were no adverse effects on beef quality and blood biochemical indexes in each group. Compared with the normal concentrate group, the OTU number and α-diversity index of rumen microorganisms of fattening cattle fed with mixed silage as the basic diet supplemented with bio-concentrate increased significantly. At generic level, the relative abundances of Prevotella, Porphyromonadaceae (unclassified), and Succiniclasticum were increased by adding bio-concentrate in the diets based on mixed silage and single sorghum silage. Relative abundances of Bacteroidetes (unclassified), Ruminococcaceae (unclassified), and Firmicutes (unclassified) decreased. In conclusion, the bio-concentrate might be a better choice than common concentrate for beef cattle breeding.

DOI: 10.15376/biores.19.2.2216-2243

Keywords: Silage feed; Finishing cattle; Concentrated feed; Growth performance; Meat quality and blood indexes; Rumen bacterial diversity; 16S rRNA sequence

Contact information: a: Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China; b: School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China; c: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic sciences and Natural Resources Research of CAS; § Co-first anthors;*Corresponding author: wangxiaoli6578@sina.com; wangxiaoli01@caas.cn

 

GRAPHICAL ABSTRACT

 

INTRODUCTION

In heavily cultivated countries such as China, the feeding system of ruminants is agricultural by-product dependent rather than grassland dependent. The efficiency of a ruminant feeding system in these countries, therefore, relies on how efficiently agricultural by-products are used. In the traditional extensive practice, beef cattle are fed crop stalks supplemented with a little concentrate. Silage such as woodgrass, hay, and crop straw is an important source of roughage for ruminants (Filik and Erturk 2023). Roughage contains a lot of crude fiber, which is an important source of energy for ruminants (Orskov 1998). Although ruminants do not produce cellulosic hydrolase or hemicellulosic hydrolase on their own, the cellulose components in the feed are broken down and fermented by the microbial flora in the rumen to produce volatile fatty acids such as acetic acid, propionic acid, and butyric acid (Castillo-González et al. 2014). Volatile fatty acids are absorbed to provide energy to the ruminants. In addition, crude fiber can also stimulate animal chewing, gastrointestinal peristalsis, enrich the gastrointestinal tract, and regulate gastrointestinal microflora (Refat and Yu 2016).

Corn, sorghum, and wheat are the main sources of roughage. However, it is difficult to meet the nutrient needs of ruminants by feeding only these roughages with low levels of protein, calcium, and phosphorus (Santra and Karim 2009). In many feedlots, adding additives to the basal diet of ruminants is a practical way to increase production. To improve production performance, management and improvement of rumen fermentation have always been the goals of ruminant research (Dias et al. 2021; Jihene et al. 2022; Várhidi et al. 2022). The addition of concentrate provides more energy for the growth of ruminants (Hill et al. 2008). The mixture of the roughage and the concentrate greatly improves the utilization rate of the feed (Coverdale et al. 2004), improves the rumen environment (Khan et al. 2011), and reduces the abnormal behavior of ruminants during growth (Muhammad et al. 2016). In addition, optimization of dry matter intake reduces feed costs and improves feeding efficiency (Suarez-Mena et al. 2015), especially at the concentrate level. Studies have shown that high concentrate levels alter the feeding time of ruminants, shortening rumination times (Devries et al. 2007; Devries and Keyserlingk 2009).

The output of China’s animal husbandry products ranks among the top in the world, but grain and feed production has always been a weak link, and the gap between supply and demand of grain as ordinary feed is getting bigger and bigger (Zhang et al. 2019; Kang et al. 2021). Therefore, finding a low-cost feed that does not adversely affect animals to replace the higher-cost traditional feed is one of the main research goals at present. Microbial fermentation is one of the ways (Yafetto et al. 2023). Nowadays, it is widely used. Based on the previous work, the research team improved the traditional general concentrate formula and added a solid fermented product. This type of feed is called bio-concentrate (Wang et al. 2017).

The study compared the growth performance, blood biochemical parameters, beef quality, and rumen bacterial diversity of different silage-based diets (corn silage, sorghum silage, sorghum, and corn silage) supplemented with the common concentrate or the biological concentrate. It was hypothesized that under the condition of a single silage diet, adding biological concentrate can improve the growth performance and beef quality of fattening cattle more effectively than adding common concentrate. The second purpose of the study was to compare the feeding effect of biological concentrate and common concentrate under the condition of mixed silage. It was hypothesized that diets supplemented with bio-concentrate would be palatable, high in energy, and provide maximum weighted gain and higher dressing percentage for fattening cattle. The goal is to reasonably develop a more nutritious, higher utilization rate and lower cost alternative than traditional ordinary feed, so as to provide a reference for beef cattle breeding.

EXPERIMENTAL

Experimental Animal Management

The study was conducted on a farm (the third farm of Dingle ecological industry group, Wuwei City) in Wuwei City, Gansu Province. There was a total of 18 castrated bulls of about 20 months of age. All fattening cattle were purchased by the farm. Animals were quarantined for 3 weeks during which time they were vaccinated for levamisole (8 mg/kg weight), and de-warmed with Albendazole mainly against the adult stages of internal parasites. After the recovery of fattening cattle, the formal experiment began. Each of the cattle was weighed and placed in an individual pen and acclimated to the environment and experimental condition, which was followed by 145 days of feeding trial. All procedures and tests followed the Regulations on the Administration of Laboratory Animals promulgated and implemented by the State Science and Technology Commission of China and relevant national laws and regulations and animals were treated humanely.

Table 1. Test Diet

Table 2. Nutrient Composition of Silage Material

Experimental treatments were arranged by a 3×2 factorial array in a completely randomized block design. The test diet was set to three levels of coarse fodder and two levels of concentrate supplementation (Table 1). Eighteen cattle were grouped according to their initial body (350kg±25kg) weight and randomly assigned to one concentrate supplementation level, each consisting of three animals. The experiment feeds consisted of silage corn and silage sorghum (Table 2) as a basal diet and concentrate mix as a supplement. The ratio of concentrate to roughage was 70:30. All the feeds were mixed evenly and prepared into total mixed ration (TMR) for feeding and adjusted feed intake according to the actual situation. The nutritional metabolism and composition of the two different concentrates are shown in Tables 3 and 4. The preparation process of the key components, solid fermented material, in the bio-concentrate was as follows: First, with bean dregs, beer pomace, and apple pomace as the fermentation base, water was added to the fermentation tank, and the ratio of material to water was 60 to 70%; Then, fermentation bacteria such as activated Aspergillus niger, Candida ruana, and Lactobacillus plantarum were added. Last, the fermentation process was started for 2 to 5 days at 30 to 40 ℃. The test diet was offered twice a day in two equal portions at 8:00 and 16:00 hours. Clean water was available all the time.

Table 3. Nutritional and Metabolic Levels of Concentrate (Air-dried Basis)

Table 4. Composition of Concentrate (Air Drying Foundation)

Determination of Slaughter Procedure and Growth Performance of Finishing Cattle

At the beginning of the feeding trial and the end of the fattening period, the fattening cattle were weighed on an empty stomach and recorded as initial and final body weights. The average daily gain (ADG) of individual fattening cattle was calculated by dividing the sum of the average daily gains over the trial period by the number of trial days. 145 days later, the slaughter was carried out at Dingle Jiahe Slaughterhouse, Wuwei City, Gansu Province, China, following the normal procedures of the National Inspection Slaughterhouse. Carcass weight was measured by weighing. The dressing percentage was calculated as carcass weight (kg)/final weight (kg)×100%.

Collection and Determination of Blood Samples of Fattening Cattle

On the last day of the fattening test, 3 h after feeding, 10 mL of blood was collected from the tail vein. After standing at room temperature for 60 min, serum was prepared by centrifugation at 2000 g for 10 min and frozen at -20 ℃ for testing. The blood sample was sent to Lanzhou University of Technology Hospital to determine the blood routine and serum biochemical indicators, which are shown in Table 7.

Analysis and Determination of Meat Quality of Finishing Cattle

To analyze physicochemical properties, samples of the longissimus muscle were collected from each of the finishing cattle. The collected longissimus muscle was minced, placed in a freeze dryer for 48 h, dampened at room temperature for 24 h, crushed, and stored in a self-sealing bag. It was used for the determination of meat moisture, crude protein (CP), crude fat (EE), and crude ash.

Meat pH was determined at multiple sites using a hand-held pH meter (Testo 205, Testo AG, Schwarzwald, Germany) with a sharp penetrating electrode, 3 times for each meat sample, and finally averaged to give meat pH. The color of the meat (lightness, L*; redness, a*; yellowness, b*) at the section of the longissimus dorsi muscle was obtained using an automatic color difference meter (Minolta, Osaka, Japan). A portion of the longissimus dorsi muscle sample (6 cm × 4 cm × 4 cm) was weighed, placed in an aluminum steamer, and cooked in boiling water for 30 min, then cooled at 0 to 4 ℃ for 2 h. A paper towel was used to remove the surface water, and the cooking loss was calculated based on the weight difference of the sample before and after cooking. A sample of meat after cooking loss was measured for the determination of shear force. Samples were taken parallel to the direction of the muscle fibers using a special sampler. The core was then sheared using a texture analyzer (TMS pro of Stirling Food Technology company, Virginia, USA) at a transverse velocity of 60 mm/min for a 1000 Newtons (N) tension/compression load cell. During this process, the maximum shear force was recorded. A portion of the longissimus dorsi muscle sample (6cm×4cm×4cm) was weighed and suspended at 0 to 4 ℃ for 24 h, and the drip loss was calculated as the weight difference before and after suspension.

Sampling and Determination of Rumen Fluid

On the last day of the fattening trial, 3 h after morning feeding, rumen fluid was collected using an oral rumen catheter inserted to a depth of approximately 200 cm. To avoid saliva contamination, the first 50 mL collected was discarded. Subsequently, 150 mL of rumen fluid was collected through an oral rumen catheter, filtered through four layers of sterile gauze, and stored in a 50 mL sterile centrifuge tube in a -80 ℃ ultra-low temperature refrigerator until microbial diversity analysis of bacterial DNA was performed. On the last day of the fattening trial, after 3 hours of morning feeding, rumen fluid was collected using an oral rumen catheter inserted to a depth of approximately 200 cm. To avoid saliva contamination, the first 50 mL collected was discarded. Subsequently, 150 mL of rumen fluid was collected through an oral rumen catheter, filtered through four layers of sterile gauze, and stored in a 50 mL sterile centrifuge tube in a -80 ℃ ultra-low temperature refrigerator until microbial diversity analysis of bacterial DNA was performed.

Rumen fluid samples were transferred to third-party testing institutions for high-throughput gene sequencing of bacterial flora. After total DNA of the sample is extracted, the double-end data is spliced, and quality control and chimera removal are carried out to obtain the final effective data. Finally, OTU division, diversity analysis, taxonomic annotation, and difference analysis of species were carried out.

Statistical Analysis

A randomized design was applied to determine the dietary effect. The animal was the experimental unit (n=45) in all analyses, as data were collected individually. Considering each of the cattle as an experimental unit, the average value of repeated measurements for each parameter was used to conduct a comparison analysis. The differences between least-square means were evaluated by Duncan’s method, where P<0.05 were considered statistically significant, and P-values <0.10 were considered trends in the data.

The original data were statistically processed by EXCEL, and the data were analyzed by the One-Way ANOVA model in SPSS 22.0 software and compared by Duncan’s multiple test. The P-values obtained were expressed in the form of means ± SE, with P<0.01 indicating a very significant difference, 0.01<P<0.05 indicating a significant difference, and 0.05<P<0.1, indicating a trend of difference. For sequencing data, multivariate statistical analyses were performed using the package ‘vegan’ from the R statistical program (R-3.5.0, Windows). To identify the featured microorganisms at the species level in different experimental groups, linear discriminant analysis (LDA) effect size (LefSe) was done using online tools (http://huttenhower.sph.harvard.edu/galaxy).

RESULTS AND DISCUSSION

Analysis of Growth Performance of Fattening Cattle

Table 5 lists the effects of diet on the growth performance of fattening cattle. The final weight of fattening cattle fed with 100% silage sorghum and mixed silage (50% silage sorghum+50% silage corn) as the basic diet and supplemented with biological concentrate was significantly higher than that of cattle fed with common concentrate (P<0.05), which was 15.34 kg and 28.67 kg higher, respectively. Correspondingly, the carcass weight of fattening cattle fed with 100% sorghum silage and mixed silage as a basic diet supplemented with biological concentrate was significantly higher than that of fattening cattle fed with a common concentrate diet (P<0.05). However, there was no significant difference in the growth performance of fattening cattle fed with 100% corn silage as the basic diet supplemented with biological concentrate and common concentrate. In addition, the growth performance of fattening cattle fed with silage sorghum was significantly better than that of fattening cattle fed with silage corn. The growth performance parameters clearly increased with varying levels of concentrate supplementation.

Analysis of Meat Quality and Chemical Composition of Beef

The beef quality parameters of fattening cattle are shown in Table 6. The pH values of beef from different fattening cattle were significantly different (P<0.05) in the range of 5.51 to 7.05. The pH of the SC-I group was slightly higher than that of the SC-II group. However, the pH of beef in the diet supplemented with biological concentrate was significantly higher than that in the diet supplemented with common concentrate (P<0.05). There was no significant difference in drip loss and cooked meat rate among the test groups (P>0.05), but the drip loss of beef of fattening cattle fed with a bio-concentrate diet was slightly higher than that of the common concentrate group. In addition, the meat color of each biological concentrate group was higher than that of the common concentrate group, and the difference in meat color among the experimental groups was not significant (P>0.05).

Analysis of the chemical composition parameters of beef in each experimental group, compared with the common concentrate group, the protein content and ash content of beef in the biological concentrate group were higher than those in the common concentrate group, but the fat content was lower than that in the common concentrate groups. The results showed that the beef chemical composition of fattening cattle was not affected by different concentrate levels (P>0.05).

Analysis of Blood Metabolites in Fattening Cattle

The serum biochemical indexes of fattening cattle were determined (Table 7). There was no significant difference among the parameters (P>0.05), and all the biochemical indexes changed within a reasonable range. The results showed that the fattening diet had no adverse effects on fattening cattle. The TG content of fattening cattle fed with single silage corn as the basic diet and biological concentrate was significantly lower than that of fattening cattle fed with an ordinary diet. TG level can reflect the level of fat metabolism, the lower the TG content, the higher the fat utilization rate, which indirectly indicates that adding bio-concentrate to the diet can improve the fat utilization rate of fattening cattle.

Table 5. Effects on Growth Performance of Beef Cattle

Means with different superscript (a, b, c and d) in the same row are significantly different (P<0.05).

Table 6. Organoleptic Quality and Meat Chemical Composition of Beef Muscle from the Steers Fed Finishing Diets Based on Silage Sorghum or Silage Corn

Means with different superscript (a, b, c and d) in the same row are significantly different (P <0.05).

Table 7. Blood Metabolites of Beef from the Steers Fed Finishing Diets Based on Silage Sorghum or Silage Corn