| Worldwide,cattle infected with Cryptosporidium,Giardia duodenalis,and Enterocytozoon bieneusi bovis often cause diarrhea,abdominal pain,and wasting,reducing production performance,meat quality,and feed conversion rate,causing some harm to the healthy development of the cattle breeding industry.The Taer Reclamation Area is one of the important agricultural and livestock production bases in the western fringe of Xinjiang,China,and the scale of beef cattle breeding has shown prosperous development at the economic level.The prevalence of three intestinal pathogens in beef cattle in this area has not been systematically investigated.Based on this,this study used molecular biology methods to examine fresh fecal samples from beef cattle in the Taer Reclamation Area to understand the infection status of the three intestinal pathogens in beef cattle and to analyze the distribution characteristics of their species/ assemblage types/genotypes.1.From January 2022 to June 2022,555 fresh meat cattle manure samples were collected from five largescale beef cattle farms in Tacheng(n= 117),Yumin(n= 126),Emin(n= 123),Tori(n= 123)and Hefeng(n=66),respectively.The results of PCR testing of 555 beef cattle manure DNA samples based on the Cryptosporidium SSU r RNA locus showed that the prevalence of Cryptosporidium infection in beef cattle in Taer Reclamation was 27.9%(155/555).Cryptosporidium infection was found in beef cattle from all five sampling areas,with the highest rate of 45.2%(60/126)in Yumin and the lowest rate of 15.4%(19/123)in Emin,with statistically significant differences(P<0.01)between the sampling areas.Cryptosporidium infection rates were 47.1%(64/136),33.3%(46/138),21.4%(30/140),and 10.6%(15/141)in beef cattle ≤3months of age,3-6 months of age,7-12 months of age,and over 1 year of age respectively,with statistically significant differences(P<0.01)between the different age groups.In summer and winter,the prevalence of Cryptosporidium infection in beef cattle was 39.4%(98/249)and 18.6%(57/306)respectively,with statistically significant differences between the seasons(P<0.01).All 155 positive Cryptosporidium PCR amplification samples were sequenced successfully and four Cryptosporidium species were identified by sequence matching,namely Cryptosporidium andersoni(97/155),Cryptosporidium bovis(31/155),Cryptosporidium ryanae(22/155)and Cryptosporidium parvum(5/155).The results of the study suggest that Cryptosporidium infection is more common in beef cattle on large-scale farms in Taer Reclamation,that infection rates correlate with seasonal and beef cattle age factors,and that human-animal Cryptosporidium species are present.2.Based on the Giardia duodenalis bg locus,PCR was performed on 555 fecal DNA samples from beef cattle,and the results showed that the prevalence of Giardia duodenalis infection in beef cattle in Taer Reclamation was 3.8%(21/555).Among the five sampling areas,Giardia duodenalis was only detected in the feces of beef cattle in Yumin and Tori counties,with infection rates of 13.5%(17/126)and 3.3%(4/123),respectively.The prevalence of Giardia duodenalis infection was 7.4%(10/136),3.6%(5/138),and 4.3%(6/140)in beef cattle ≤3 months of age,3-6 months of age,and 7-12 months of age,respectively,and no infection was found over 1 year of age,with statistically significant differences(P<0.05)in the prevalence of Giardia duodenalis infection in beef cattle at different ages.In summer,the prevalence of Giardia duodenalis infection in beef cattle was 8.4%(21/249),and in winter,no infections were found,with statistically significant differences(P<0.01)in the prevalence of Giardia duodenalis infection in beef cattle between seasons.All 21 Giardia duodenal PCR-amplified positive samples were sequenced successfully,and all were found to be cluster E(21/21)by sequence matching.The results suggest that Giardia duodenalis infections in beef cattle on large-scale farms in the Taer Reclamation area are low and mainly infected with the host-specific cluster assemblage E.3.Based on the Enterocytozoon bieneusi ITS sequences,PCR was performed on 555 fecal DNA samples from beef cattle,showing a 5.6%(31/555)prevalence of intestinal microsporidia infection in beef cattle in Taer Reclamation.Among the five sampling areas,Enterocytozoon bieneusi infection rate was the highest in Emin at 15.4%(19/123),no infection was found in Hefeng,and the statistical difference in Enterocytozoon bieneusi infection rate among beef cattle in different sampling areas was highly significant(P<0.01).Enterocytozoon bieneusi infection rates in beef cattle <3 months old,3-6 months old,and 7-12 months old were 14.7%(20/136),6.5%(9/138),1.4%(2/140),and no infections were found in beef cattle over 1 year of age,with statistically significant differences in the prevalence of Enterocytozoon bieneusi infection in beef cattle of different ages(P<0.01).In summer and winter,the prevalence of Enterocytozoon bieneusi infection in beef cattle was 3.6%(9/249)and 7.2%(22/306)respectively,with statistically highly significant differences(P<0.01).All 31 positive Enterocytozoon bieneusi PCR amplification samples were sequenced successfully,and five known Enterocytozoon bieneusi genotypes were identified by sequence matching,namely genotypes J(17/31),I(8/31),BEB4(4/31),BEB6(1/31)and CM9(1/31),and all five genotypes belonged to Group 2.The results suggest that Enterocytozoon bieneusi infection in beef cattle on large-scale farms in Taer Reclamation is low and mainly infects host-specific genotypes J and I.In summary,it was found that there were differences in the infection rates of the three intestinal pathogens in beef cattle in Taer Reclamation,and their species,aggregates,and genotypes showed host-specific genetic distribution characteristics with some genetic diversity. |
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