Abstract:This experiment aimed to investigate the effects of compound selamectin preparation on the food intake,flea reduction rate,serum biochemical,antioxidant,immune,and inflammatory indices in flea-infected cats.A total of 24 healthy Linqing Lion cats were selected and randomly divided into four groups,with six replicates per group and one cat per replicate.The control group(Group Ⅰ)was neither infected with fleas nor administered medication.Group Ⅱ was infected with 100 fleas per cat and transdermally administered imidacloprid at 10 mg/kg once 24 hours post-infection.Groups Ⅲ and Ⅳ were each infected with 100 fleas per cat and received a single transdermal administration of the compound selamectin preparation at 0.1 mL/kg and 0.2 mL/kg,respectively,24 hours post-infection.Observations were conducted for 28 days after administration.The results showed that on the 0 day of administration,compared with GroupⅠ,the average daily food intake of Groups Ⅱ,Ⅲ,and Ⅳ was significantly decreased(P<0.05).The serum concentrations of total protein(TP),albumin(ALB),immunoglobulin G(IgG),and immunoglobulin M(IgM),and the activiy of superoxide dismutase(SOD)and total antioxidant capacity(T-AOC)were significantly decreased(P<0.05).The serum concentrations of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),and C-reactive protein(CRP)were significantly increased(P<0.05).On the 28 day of administration,there were no significant differences in any of the measured indices among all groups(P>0.05).The study shows that flea infection can effect the food intake,serum biochemical,antioxidant,immune,and inflammatory indices in cats.Administration of the compound selamectin preparation at doses of 0.1 mL/kg and 0.2 mL/kg can improve the daily food intake,flea reduction rate,and the aforementioned serum indices in flea-infected cats.

Abstract:Malic acid,a dicarboxylic acid widely found in nature,serves as a key intermediate metabolite in the tricarboxylic acid cycle(TCA).Among them,L-malic acid,the predominant natural isomer,has become a research hotspot in animal nutrition due to its easy absorption,direct involvement in energy metabolism,and green and safe properties.L-malic acid possesses biological functions such as anti-inflammatory,antioxidant,and regulation of microbial flora,effectively alleviating oxidative stress and inflammatory states in animals,enhancing intestinal barrier integrity,and thereby improving growth performance,meat quality,and antioxidant capacity.In ruminants,L-malic acid can optimize ruminal fermentation parameters,enhance production performance and nutrient utilization,and help reduce methane emissions.This article reviews the biological characteristics,metabolic pathways,functional mechanisms,and application effects of L-malic acid in animal production,providing a reference for L-malic acid further development and utilization in animal production.

Abstract:This experiment aimed to investigate the effects of dietary supplementation with flaxseed oil and flaxseed on the morphology of the compound stomach and small intestine,as well as digestive enzyme activities in cashmere goat lambs.A total of 60 healthy,four-month-old weaned castrated male lambs with similar body weight were randomly divided into three groups,with four replicates per group and five lambs per replicate.The control group(group CON)was fed a total mixed ration(TMR,with a concentrate-to-forage ratio of 50∶50).The flaxseed oil group(group FLO)was fed TMR+flaxseed oil.The supplementation levels of flaxseed oil during the early,middle,and late fattening stages were 2.23%,2.23%,and 2.79%,respectively.The flaxseed group(group FLS)was fed TMR+heat-treated flaxseed(replacing an equivalent amount of flaxseed oil based on an oil extraction rate of 36%).The pre-test period was 14 days,and the formal test period was 90 days.The results showed that the activities of lipase and amylase in the ileum and the rumen wall thickness in group FLO were significantly higher than those in group CON(P<0.05),the duodenal villus width and the lipase activities in the duodenum and jejunum were significantly higher than those in group FLS(P<0.05).The duodenal crypt depth in group FLS was significantly higher than that in group CON(P<0.05),whereas the muscular layer thickness of the reticulum wall and the ileal crypt depth were significantly lower than those in group CON(P<0.05).For the lambs,the villus height in jejunum,villus width in ileum,villus height to crypt depth ratio in jejunum,and trypsin activities in the duodenum and pancreas showed a pattern:Group FLO>group CON>group FLS(P<0.05).The chymotryp activity in the duodenum of lambs showed a pattern:Group FLO>group FLS>group CON(P<0.05).The study shows that dietary flaxseed oil improves growth and development in the rumen,duodenum,and jejunum of lambs,and stimulates the secretion of digestive enzymes in the duodenum and ileum.In contrast,the inclusion of flaxseed conversely inhibits the development of the rumen,reticulum,omasum,and small intestine,and also impedes the secretion of certain digestive enzymes in the small intestine and pancreas.

Abstract:To deeply investigate the relationship between digital innovation capability and the green development of livestock enterprises,this study was based on relevant data from 60 listed animal husbandry enterprises in China from 2012 to 2024,using empirical research methods,systematically examined the impact of digital innovation capability on the green and high-quality development of animal husbandry enterprises.The results showed that digital innovation capability had a significant positive promoting effect on the green and high-quality development of livestock enterprises,and this conclusion remained valid after endogeneity treatment and a series of robustness tests.The mediation effect test indicated that corporate R&D expenditure,production technology efficiency,and financing scale played partial mediating roles in the pathway through which digital innovation capability affects green and high-quality development.The study shows that strengthening digital innovation capability is an important path to drive livestock enterprises to achieve green and high-quality development.

Abstract:Based on panel data from five major broiler-producing provinces in China from 2014 to 2023,this arctile comprehensively employs multiple measurement methods to empirically analyze the impact of breeding scale on the cost efficiency of broiler farming and its mechanism.The results showed that breeding scale had a significant positive effect on the cost efficiency of broiler farming,and this conclusion remained valid after a series of robustness tests.The mediation effect test indicated that technological upgrading played a partial mediating role in the process of breeding scale improving cost efficiency.Furthermore,the moderation effect analysis revealed that environmental regulation exerted a significant positive moderating function in this process.The study indicates that moderately promoting the expansion of breeding scale,coupled with coordinated efforts to advance technological upgrading and strengthen environmental regulation guidance,serves as an effective pathway to enhance the cost efficiency and industrial competitiveness of broiler farming.

Abstract:This experiment aimed to investigate the effects of dietary supplemented with rosemary extract on the lactation performance,serum biochemical indexes,rumen fermentation parameters,and microbial community in dairy cows.A total of 30 healthy,freshly calved Holstein cows with good physical condition,the same parity,and in the lactation period were selected and randomly divided into two groups,with 15 replicates per group and one cow per replicate.The control group was fed a basal diet,while the experimental group received the basal diet supplemented with 20 g/(head·d)of rosemary extract.The pre-trial period was 18 days,and the formal trial period was 30 days.The results showed that compared with the control group,there were no significant differences in milk yield,milk fat percentage,milk protein percentage,lactose percentage,and somatic cell count in the experimental group(P>0.05).The levels of urea nitrogen(BUN),glucose(GLU),and blood ammonia(BA)were significantly reduced(P<0.05),and triglyceride(TG)was extremely reduced(P<0.01),and the non-esterified fatty acid(NEFA)content in the serum of the experimental group was extremely increased(P<0.01).The propionic acid content in the rumen fluid of the experimental group was significantly increased(P<0.05),while the acetic acid content and acetic acid to propionic acid ratio were significantly decreased(P<0.05).There was no significant difference in alpha diversity between the two groups(P>0.05).At the genus level,the relative abundance of Rikenella in the experimental group was significantly increased(P<0.05),while the relative abundances of Lentimicrobium and Eisenbergiella were significantly decreased(P<0.05).The study shows that dietary supplementation with rosemary extract can improve rumen fermentation function and lipid metabolism of dairy cow by modulating the rumen microbial structure.

Abstract:This experiment aimed to screen Medicago sativa varieties suitable for cultivation in the Hexi Corridor region.Twelve domestic and international Medicago sativa varieties were selected,and their agronomic traits,forage yield,and nutritional quality indicators were measured to comprehensively evaluate the production performance and feeding value of each variety.Fuzzy mathematics and grey relational analysis were comprehensively applied for variety ranking.The results showed that in terms of agronomic traits,the plant height of Salt-Tolerant Star was the highest,reaching 115.33 cm,the stem thickness of Knight was the largest,reaching 3.35 mm,the stem-to-leaf ratio in descending order was Gannong No.9>Knight>Salt-Tolerant Star>Giant Salt-Tolerant>Prospect>Adina>Zhongmu No.1>Thunder>Victoria>Zhongmu No.2>Polar Bear>Gannong No.3.In terms of yield,Prospect had the highest annual hay yield,reaching 15.93 t/hm2.Giant Salt-Tolerant had the largest fresh-to-dry ratio,reaching 4.90.Regarding nutritional quality,Zhongmu No.1 had the highest crude protein(CP)content,reaching 20.83%.Adina had the lowest neutral detergent fiber(NDF)content,at 31.59%.Gannong No.3 had the lowest acid detergent fiber(ADF)content,at 28.26%.Knight had the highest crude fat(EE)content,reaching 3.18%,and Gannong No.9 had the highest crude ash(Ash)content,reaching 12.15%.The study shows that based on comprehensive consideration of relative feed value(RFV),relative forage quality(RFQ),grading index(GI)for coarse feed,fuzzy comprehensive evaluation,and grey relational analysis results,the five varieties of Zhongmu No.1,Adina,Gannong No.9,Zhongmu No.2,and Knight exhibit excellent comprehensive production performance and nutritional quality,making them suitable for promotion and cultivation in the Hexi Corridor region.

Abstract:This experiment aimed to investigate the effects of different intercropping patterns of wild soybean and sorghum hybrid sudangrass on the forage production performance and nutritional quality.Three intercropping modes were tested:2 rows of wild soybean+1 row of sorghum hybrid sudangrass(2∶1,group G2P1),1 row of wild soybean+1 row of sorghum hybrid sudangrass(1∶1,group G1P1),and 1 row of wild soybean+2 rows of sorghum hybrid sudangrass(1∶2,group G1P2),with monoculture of wild soybean(group G)and sorghum hybrid sudangrass(group P)as control.By conducting field experiments,the agronomic traits,production performance,and nutritional quality of each group were determined,and the weighted membership function method was used for comprehensive evaluation.The results showed that the plant height of sorghum hybrid sudangrass in the group G1P1 was 3.02 m,and a stem thickness was 16.83 mm,and the plant height of wild soybean was 1.79 m,and stem thickness was 1.42 mm,significantly higher than other groups.The mixed harvest forage total protein yield(3 287.12 kg/hm2)and relative feeding value(154.77)of the group G1P1 were the highest.The stem to leaf ratio of intercropping mode was higher than that of monoculture mode.The group G1P2 had the highest yield of mixed fresh grass yield(188 712.13 kg/hm2)and hay yield(41 516.67 kg/hm2).The ranking result of the weighted membership function was:Group G1P1>group G>group G1P2>group G2P1>group P.The study shows that the intercropping of wild soybean and sorghum hybrid sudangrass in the ratio of 1∶1 can increase the production performance and nutritional quality of forage,and improve the land utilization rate,which is a better planting mode.

Abstract:The experiment aimed to investigate the effects of starter diet protein levels on the serum immune,antioxidant,and hormone indices of suckling donkey foals.A total of 21 healthy female donkey foals of two-month-old with an average body weight of(52.0±2.5)kg were selected and randomly divided into three groups,with seven replicates per group,and one donkey foal per replicate.They were respectively fed starter feed with protein levels of 20.03%(high protein group),18.02%(medium protein group),and 16.01%(low protein group).The pre-test period was 15 days.The formal test period was 45 days.The results showed that the body height,bady length,and chest circumference of the donkey foals in each group were similar,with no significant differences(P>0.05).As the protein level of the starter diet increased,the serum immunoglobulin G(IgG)content in donkey foals was significantly increased(P<0.05),and the interleukin-1β(IL-1β)content was significantly decreased(P<0.05).The serum immunoglobulin M(IgM)content in the high protein group was significantly higher than that in the low and medium protein groups(P<0.05),and the interleukin-2(IL-2)content in the medium protein group was significantly higher than that in the low and high protein groups(P<0.05).The activities of serum catalase(CAT)and superoxide dismutase(SOD)in the medium and high protein groups were significantly higher than those in the low protein group(P<0.05),and the activity of glutathione peroxidase(GSH-Px)in the high protein group was significantly higher than that in the low and medium protein groups(P<0.05).The content of malondialdehyde(MDA)in the medium and high protein groups was significantly lower than that in the low protein group(P<0.05).The levels of serum adiponectin(ADP)and insulin-like growth factor-1(IGF-1)in the high protein group were significantly higher than those in the low and medium protein groups(P<0.05).The study shows that when the protein level in the starter diet is from 18.02%and 20.03%,it can enhance the immune function and antioxidant capacity,and promote the glucose and lipid metabolism of donkey foals.

Abstract:Based on provincial panel data from 2013 to 2023,this study employs the entropy method and the Dagum Gini coefficient approach to analyze the level and regional disparities of high-quality development in Chinese mutton sheep industry.Furthermore,a regression model is used to identify its key influencing factors.The results showed that during the sample period,the high-quality development level of Chinese mutton sheep industry exhibited a fluctuating upward trend.From a regional distribution perspective,the growth trends of the four major regions were generally consistent,but there were significant regional disparities,with the western region ranking the highest,followed by the central and eastern regions,and relatively lower levels in the northeastern region.The main source of the overall differences in the high-quality development level of the mutton sheep industry in China was that the regional disparities are relatively stable,while the disparities between regions are the main component.Regression analysis indicated that non-agricultural income,natural resource conditions,urbanization rate,professional technical personnel input,and the degree of breeding specialization all exerted a significant positive promoting effect on the high-quality development of the mutton sheep industry.Research shows that regional imbalance is a prominent feature of the high-quality development of Chinese mutton sheep industry.Coordinating regional development and optimizing factor input are the key paths to promoting the overall quality improvement and efficiency enhancement of the industry.

Abstract:This experiment aimed to investigate the effects of different selenium sources on the growth and reproduction,antioxidant,and immune response in Apis cerana.A total of 12 healthy Apis cerana colonies with comparable strength,queens of similar onset of egg-laying,and stable egg production were randomly divided into four groups with three replicates per group,and one swarm per replicate.The control group received a basal diet,while the experimental groups were supplemented with 0.5 mg/kg of sodium selenite,selenium yeast,and nano-selenium,respectively.The pre-test period was seven days,and the formal test period was 21 days.The results showed that compared with the control group,experimental groups exhibited significantly increased pupation rate,pupal weight,eclosion rate,and newborn bee weight(P<0.05).The growth indexes of the yeast selenium group and nano selenium group were significantly higher than those of the sodium selenite group(P<0.05).There was no significant difference in the first-day egg-laying quantity per bee in the experimental groups(P>0.05),while the yeast selenium group and nano selenium group significantly increased the average daily egg-laying quantity per bee(P<0.05).The activity of superoxide dismutase in the experimental groups was significantly increased(P<0.05),while the activities of catalase and glutathione peroxidase were significantly increased in the yeast selenium group and nano selenium group(P<0.05).The relative gene expression levels of defensin,abaecin,and hymenoptaecin in experimental groups were significantly increased(P<0.05).The study shows that different selenium sources can promote the growth and reproduction of Apis cerana,enhance antioxidant capacity and immune function,among which yeast selenium and nano selenium have better effects.

Abstract:Based on panel data from 30 provinces in China from 2014 to 2024,this article empirically analyzed the effect of artificial intelligence on the resilience of feed industry chain and supply chain,as well as its underlying mechanisms.The results showed that artificial intelligence had a significant promoting effect on the resilience of the feed industry chain and supply chain.Heterogeneity analysis revealed that this promoting effect was more prominent in eastern regions and areas with higher levels of artificial intelligence development.Mechanism tests demonstrated that artificial intelligence enhanced the resilience of the feed industry chain and supply chain by driving the development of new quality productive forces.The study shows that artificial intelligence serves as a key driver in enhancing the resilience of the feed industry chain and supply chain,providing reference for promoting high-quality development in the feed industry.

Abstract:The experiment aimed to investigate the effects of adding different levels of ammonium chloride to the diet on the morphology,fatty acid composition,lipidomics,and volatile flavor compounds of intramuscular adipose tissue in Tibetan sheep.A total of 80 healthy two-month-old early weaned Tibetan ewes with an average weight of(16.22±1.01)kg were randomly divided into four groups,with five replicates per group and four ewes per replicate.Each group was supplemented with 0(group CON),1.49%(group NH1),2.24%(group NH2),and 3.01%(group NH3)of ammonium chloride in the basal diet,respectively.The pre-test period was 15 days,and the formal test period was 90 days.The results showed that the groups NH2 and NH3 had different sizes and disordered arrangement of adipocytes,and the group NH3 showed cell rupture.The addition level of ammonium chloride had a significant effect on the density and diameter of adipocytes(P<0.05),as well as on the concentrations of intramuscular saturated fatty acids(SFA),monounsaturated fatty acids(MUFA),polyunsaturated fatty acids(PUFA),n-3 polyunsaturated fatty acids(n-3 PUFA),and n-6 polyunsaturated fatty acids(n-6 PUFA)(P<0.05).A total of 198 differential lipid molecules were screened by pairwise comparison of each group of samples,most of which were glycerides such as diglycerides and triglycerides,as well as glycerophosphatide such as phosphatidylcholine and phosphatidylethanolamine.The addition level of ammonium chloride in feed had a significant effect on the content of volatile flavor compounds in intramuscular fat(P<0.05).The study shows that when the level of ammonium chloride added to feed is≥2.24%,it can reduce the accumulation of functional fatty acids and characteristic flavor compounds in intramuscular fat by disrupting the structure of adipocytes,inhibiting fatty acid synthesis and metabolism.Meanwhile,the significant accumulation of ammonia in intramuscular fat ultimately has a negative impact on the flavor and quality of Tibetan sheep.

Abstract:This experiment aimed to investigate the polymorphism of the calpain Ⅰ(CAPN1)gene in Zaosheng cattle and its effects on meat production traits,assessing its potential as a candidate functional gene influencing meat production traits.A total of 320 blood samples were collected from Zaosheng cattle.Single nucleotide polymorphism(SNP)sites of the CAPN1 gene were detected by direct sequencing to analyze their association with meat production traits.Meanwhile,real-time quantitative PCR(RT-qPCR)was employed to detect the mRNA expression levels of this gene in different tissues and individuals with different genotypes.The results showed that three SNP sites were identified within the CAPN1 gene,namely A3854G,C5709G,and G11058A.Association analysis revealed that the C5709G site was significantly correlated with live weight before slaughter and loin eye area(P<0.05),while the G11058A site was significantly correlated with loin eye area and shear force(P<0.05).The CAPN1 gene was expressed in leg muscle,longissimus dorsi muscle,liver,and heart,with expression levels progressively increasing from leg muscle to heart.At the G11058A site,the relative mRNA expression level in individuals with the FF genotype was significantly higher than that in individuals with the EE genotype(P<0.05).Pearson correlation analysis further indicated that the CAPN1 gene expression level was significantly correlated with shear force and loin eye area(P<0.05).The study shows that the G11058A site of the CAPN1 gene is significantly associated with certain meat production traits in Zaosheng cattle and can serve as a potential genetic marker for selective breeding of meat production traits in this breed.

Abstract:The experiment aimed to investigate the effects of different dietary protein levels on the growth performance,serum biochemical indicators,and antioxidant capacity of Siniperca chuatsi.A total of 300 healthy Siniperca chuatsi with an initial body weight of(11.10±0.53)g were selected and randomly divided into five groups,with three replicates per group and 20 fish per replicate.Groups B1 to B5 were fed with feeds containing protein levels of 40.20%,45.06%,49.92%,54.79%and 59.65%,respectively.The pre-test period was 14 days,and the formal test period was 42 days.The results showed that the weight gain rate(WGR)and specific growth rate(SGR)of group B3 were significantly higher than those of group B1(P<0.05).The analysis of the line model showed that when the protein content of the feed for the Siniperca chuatsi was 50.94%to 51.29%,the growth performance was better.The serum albumin and globulin concentrations in group B5 were significantly higher than those in group B2(P<0.05).The pepsin activity in the foregut and midgut of group B3 was significantly higher than those of the other groups(P<0.05).Analysis of liver antioxidant capacity showed that the superoxide dismutase activity in the liver of group B3 was significantly higher than that of groups B4 and B5(P<0.05),while the malondialdehyde content was significantly lower than that of groups B4 and B5(P<0.05).The study shows that dietary protein level of 49.92%can significantly improve the growth performance,protein utilization efficiency,and liver antioxidant capacity of Siniperca chuatsi,and it is recommended to set the protein content in the feed at around 50.00%for optimal results.

Abstract:This experiment aimed to investigate the effects of dietary quercetin supplementation on the growth performance,muscle nutritional composition,hepatic antioxidant enzyme activities,and immune-related gene expression levels in juvenile Carassius auratus.A total of 300 healthy juvenile Carassius auratus with an initial body weight of(4.82±2.10)g were randomly divided into four groups,with three replicates per group and 25 fish per replicate.The control group(group CON)was fed a basal diet,while groups LQE,MQE,and HQE were fed the basal diet supplemented with 50,100,and 200 mg/kg quercetin,respectively.The pre-test period was seven days,and the formal test period was 56 days.The results showed that compared with group CON,the weight gain rate and specific growth rate in group HQE were significantly increased(P<0.05),and the hepatosomatic index was significantly decreased(P<0.05).Superoxide dismutase(SOD)activity in groups LQE,MQE,and HQE was significantly increased(P<0.05),and malondialdehyde(MDA)content was significantly decreased(P<0.05).Catalase(CAT)and alanine aminotransferase(ALT)activities in group LQE were significantly increased(P<0.05).CAT and alkaline phosphatase(AKP)activities in group MQE were significantly increased(P<0.05).Acid phosphatase(ACP),AKP,ALT,aspartate aminotransferase(AST),and glutathione peroxidase(GSH-Px)activities in group HQE were significantly decreased(P<0.05).The relative expression levels of tumor necrosis factor-α(TNF-α),interleukin-8(IL-8),transforming growth factor-β1(TGF-β1),interleukin-10(IL-10),and CXC chemokine receptor 1(CXCR1)in group HQE were significantly increased(P<0.05).Histological observation indicated that group MQE had no adverse effects on the liver of Carassius auratus,whereas group HQE caused slight damage to hepatocytes.The study shows that a quercetin supplementation level of 200 mg/kg yields the optimal promoting effect on the growth and development of Carassius auratus,while a level of 100 mg/kg enhances hepatic antioxidant capacity and provides the optimal protective effect on the liver.

Abstract:This experiment aimed to screen alfalfa varieties suitable for cultivation in saline-alkali soils.Using 12 alfalfa varieties as test materials,the petri dish filter paper germination method was employed.Five sodium chloride(NaCl)concentration gradients were set,included 0(control group),20,40,60,and 80 mmol/L.Eight germination indices were measured,and salt tolerance was comprehensively evaluated using correlation analysis,principal component analysis,and the membership function method.The results showed that as the salt concentration increased,the germination of all varieties was inhibited to varying degrees,with higher concentrations leading to more pronounced inhibition.Membership function analysis revealed that ZC76 had the highest comprehensive evaluation value(D value)of 0.88,ranking first and exhibiting the best salt tolerance among all tested materials.Next were Zhongcao NO.35(ZC35H),Zhongcao NO.13(ZC13H),59N59,and Zhongcao NO.46(ZC46H),with D values of 0.68,0.66,0.63,and 0.56,respectively.The D value of Gannong NO.3(GN3H)was 0.21,indicating the worst salt tolerance of all varieties.The salt tolerance of the 12 varieties,from strong to weak,was as follows:ZC76>ZC35H>ZC13H>59N59>ZC46H>Zhongmu NO.5(ZM5H)>Salt tolerant star(NYZX)>Target(BB)>ZC75>WL298>Zhongmu NO.3(ZM3H)>GN3H.The study shows that salt stress significantly inhibits alfalfa germination,and there are clear differences in salt tolerance among varieties.ZC76,ZC35H,ZC13H,59N59,and ZC46H exhibit strong salt tolerance and are suitable for promotion and cultivation in saline-alkali soil regions.

Abstract:The experiment aims to analyze the basic enzymatic properties of the highly expressed cellulase CMX-1 screened from the gayal rumen Fosmid library.To further improve the catalytic efficiency of the enzyme,the CMX-1 encoding gene was mutated and modified using error-prone polymerase chain reaction(ep-PCR).The results showed that the mutant gene EMX-1 was successfully obtained.Sequence analysis revealed that EMX-1 encodes 305 amino acids(aa),with a theoretical molecular weight of 34.29 kDa and an isoelectric point(pI)of 5.70.It belongs to the glycoside hydrolase family 5(GH5)and shares a maximum sequence similarity of 80%with homologous sequences in the GenBank database.The mutant gene was efficiently expressed in Escherichia coli BL21 and exhibited cellulase activity.Enzymatic characterization results showed that the optimal temperature of the mutant enzyme EMX-1 was the same as that of the original enzyme CMX-1,both at 50℃.At this temperature,the optimal pH value of EMX-1 increased from 5.0 of CMX-1 to 5.5.At their respective optimal pH value and 50℃conditions,the cellulase activity of EMX-1 was 247.76 U/mL,which was about 1.4 times higher than that of CMX-1(178.92 U/mL).EMX-1 exhibited stronger stability than CMX-1 within the temperature range of 40 to 50℃and pH value of 3.0 to 9.0.The study shows that this study successfully obtained the mutated enzyme EMX-1 with significantly improved catalytic performance through ep-PCR technology,providing new enzyme resources for the development of ruminant feed additives.

Abstract:This experiment aimed to investigate the effects of dietary scygonadin supplementation on the growth performance,blood indexes,nutrient apparent digestibility,and intestinal health in adult Chinese rural cats.A total of 30 adult neutered male Chinese rural cats were randomly divided into two groups,with 15 replicates per group and one cat per replicate.The control group was fed a basal diet,while the experimental group was fed a basal diet supplemented with 0.1%scygonadin.The pre-test period was seven days,and the formal test period was 28 days.The results showed that compared with the control group,the experimental group exhibited no significant differences in growth performance and fecal scores(P>0.05).The eosinophil percentage and count in the experimental group were significantly decreased(P<0.05),while plasma levels of total protein,globulin,and immunoglobulin G(IgG)were significantly increased(P<0.05),there was no significant difference in the level of interleukin-10(IL-10)(P>0.05).The apparent digestibility of carbohydrates in the experimental group was significantly increased(P<0.05).For intestinal health,the plasma calprotectin contentand diamine oxidase(DAO)activity in the experimental group were significantly decreased(P<0.05).The study shows that dietary supplementation with 0.1%scygonadin can promote carbohydrate digestion and absorption,enhance immune function,and improve intestinal barrier integrity,thereby contributing to the maintenance of intestinal health in Chinese rural cats.

Abstract:Grazing intensity is a key factor affecting the production performance and nutritional quality of forage in alpine grasslands.Moderate grazing can maintain root health and photosynthetic efficiency,improve vegetation diversity and community stability.Although heavy grazing can improve the nutritional quality of grass in the short term,such as increasing the content of crude protein,crude fat,and crude ash,and reducing the content of neutral detergent fiber and acid detergent fiber,long-term heavy grazing can lead to grassland degradation and decreased grass productivity.This study focuses on exploring the effects of different grazing intensities on the production performance and nutritional quality of alpine grassland forage in Qinghai-Xizang Plateau region,aiming to clarify the appropriate grazing intensity and provide reference for the health and sustainable development of alpine grassland ecosystems.Based on existing research,it is recommended to control the appropriate livestock carrying capacity in the high-altitude grasslands of the Qinghai-Xizang Plateau within the range of 5 to 6 sheep units/hm2.