RESUMO
The objective of this study was to evaluate the effect of either a limited forage intake or concentrate supplementation prior to the adaptation to high-concentrate diets on dry matter intake, ruminal pH, bacteria, and protozoa of Nellore cattle. The experiment was designed as a two 3×3 Latin square, and six cannulated Nellore steers were used. Each experimental period was composed by three feeding phases: pre-adaptation (14 days), adaptation (12 days), and finishing (seven days) diet, in a total of 33 days per period. The steers were assigned to one of three pre-adaptation dietary treatments: control (Tifton hay fed ad libitum + mineral supplement), restriction (Tifton hay fed at 1.4% of BW + mineral supplement), and concentrate (Tifton hay fed ad libitum + 0.5% of BW of a mix of concentrate feedstuffs and mineral supplement). The adaptation period consisted of two adaptation diets, which contained 72 and 79% concentrate for six days each. The finishing diet contained 86% concentrate. During the pre-adaptation phase, restricted cattle had higher pH than concentrate-fed cattle. There was a reduction in M. elsdenii relative population in cattle from either restriction or concentrate groups. During adaptation and finishing phases, cattle from concentrate group had smaller F. succinogenes populations compared with the control group. The previous nutritional backgrounds impact ruminal microbiota during adaptation and finishing phases without causing any negative effect on ruminal pH. Feeding concentrate prior to the adaptation positively impacted the transition to high-concentrate diets and promoted increased dry matter intake.(AU)
Assuntos
Animais , Bovinos/fisiologia , Microbiota/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Rúmen/fisiologia , Necessidades Nutricionais/fisiologiaRESUMO
The objective of this study was to examine the relationships among ruminal microbial community, rumen morphometrics, feeding behavior, feedlot performance, and carcass characteristics of Nellore cattle, classified by residual feed intake (RFI). Twenty-seven Nellore yearling bulls with an initial body weight (BW) of 423.84 ± 21.81 kg were fed in feedlot for 107 d in individual pens to determine the RFI phenotype. Bulls were categorized as high RFI (>0.5 SD above the mean, n = 8), medium RFI (±0.5 SD from the mean, n = 9), and low RFI (<0.5 SD below the mean, n = 10). At harvest, whole rumen content samples were collected from each bull to evaluate ruminal microbial community, including bacteria and protozoa. The carcass characteristics were determined by ultrasonography at the beginning and at the end of the experimental period, and behavior data were collected on d 88. As a result of ranking Nellore bulls by RFI, cattle from low-RFI group presented lesser daily dry matter intake (DMI), either in kilograms (p < 0.01) or as percentage of BW (p < 0.01) than high-RFI yearling bulls, resulting in improved gain:feed (G:F). However, variables, such as average daily gain (ADG), final BW, hot carcass weight (HCW) and other carcass characteristics did not differ (p > 0.05) across RFI groups. The eating rate of either dry matter (DM )(p = 0.04) or neutral detergent fiber (NDF) (p < 0.01) was slower in medium-RFI yearling bulls. For ruminal morphometrics an RFI effect was observed only on keratinized layer thickness, in which a thinner layer (p = 0.04) was observed in low-RFI Nellore yearling bulls. Likewise, Nellore yearling bulls classified by the RFI did not differ in terms of Shannon's diversity (p = 0.57) and Chao richness (p = 0.98). Our results suggest that the differences in feed efficiency of Nellore bulls differing in phenotypic RFI should be attributed to metabolic variables other than ruminal microorganisms and epithelium, and deserves further investigation.
RESUMO
Beef cattle are key contributors to meat production and represent critical drivers of the global agricultural economy. In Brazil, beef cattle are reared in tropical pastures and finished in feedlot systems. The introduction of cattle into a feedlot includes a period where they adapt to high-concentrate diets. This adaptation period is critical to the success of incoming cattle, as they must adjust to both a new diet and environment. Incoming animals are typically reared on a variety of diets, ranging from poor quality grasses to grazing systems supplemented with concentrate feedstuffs. These disparate pre-adaptation diets present a challenge, and here, we sought to understand this process by evaluating the adaptation of Nellore calves raised on either grazing on poor quality grasses (restriction diet) or grazing systems supplemented with concentrate (concentrate diet). Given that nutrient provisioning from the diet is the sole responsibility of the ruminal microbial community, we measured the impact of this dietary shift on feeding behavior, ruminal fermentation pattern, ruminal bacterial community composition (BCC), and total tract digestibility. Six cannulated Nellore bulls were randomly assigned to two 3 × 3 Latin squares, and received a control, restriction, or concentrate diet. All cohorts were then fed the same adaptation diet to mimic a standard feedlot. Ruminal BCC was determined using Illumina-based 16S rRNA amplicon community sequencing. We found that concentrate-fed cattle had greater dry matter intake (P < 0.01) than restricted animals. Likewise, cattle fed concentrate had greater (P = 0.02) propionate concentration during the adaptation phase than control animals and a lower Shannon's diversity (P = 0.02), relative to the restricted animals. We also found that these animals had lower (P = 0.04) relative abundances of Fibrobacter succinogenes when compared to control animals during the pre-adaptation phase and lower abundances of bacteria within the Succinivibrio during the finishing phase, when compared to the control animals (P = 0.05). Finally, we found that animals previously exposed to concentrate were able to better adapt to high-concentrate diets when compared to restricted animals. Our study presents the first investigation of the impact of pre-adaptation diet on ruminal BCC and metabolism of bulls during the adaptation period. We suggest that these results may be useful for planning adaptation protocols of bulls entering the feedlot system and thereby improve animal production.
RESUMO
BACKGROUND: Intraoral lesions clinically suspicious for cancer/precancer should be biopsied and diagnosed histopathologically. We evaluated whether the frequency of oral cancer (OC) cases diagnosed in Puerto Rico (PR) is disproportionately high relative to the frequency of persons with histopathologic diagnoses that would have appeared clinically suspicious for OC/precancer at biopsy. METHODS: All pathology reports for oral (ICD-O-3 C01-C06) soft tissue biopsies generated during 1/2004-5/2005 by seven PR and two New York City (NYC) pathology laboratories were reviewed. The analysis was restricted to persons diagnosed with invasive oral squamous cell carcinoma (OSCC), epithelial dysplasia, or hyperkeratosis/epithelial hyperplasia (HK/EH), i.e., diagnoses associated with lesions clinically suspicious for OC/precancer. The OC relative frequency measured the percentage of persons diagnosed with OSCC among persons with OSCC, dysplasia, or HK/EH. OC relative frequencies for PR and NYC laboratories were compared. RESULTS: Overall, the OC relative frequency was 67% in PR and 40% and 4% in the NYC general and oral pathology laboratories, respectively (each p<0.001). In PR, the OC relative frequency was highest for males (80%). When OC relative frequencies were stratified by pathology laboratory type (general/oral) and compared across PR and NYC, age/gender-specific OC relative frequencies were always higher in PR; however, differences were consistently statistically significant for males only. CONCLUSION: A disparity in the OC relative frequency exists in PR vs. NYC indicating a shortfall in biopsying potentially precancerous oral lesions in PR. PR residents with intraoral lesions suspicious for oral cancer/precancer are most likely to be biopsied only after developing an invasive OC.
Assuntos
Biópsia/estatística & dados numéricos , Carcinoma de Células Escamosas/patologia , Laboratórios/normas , Neoplasias Bucais/patologia , Lesões Pré-Cancerosas/patologia , Neoplasias de Tecidos Moles/patologia , Fatores Etários , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/epidemiologia , Transformação Celular Neoplásica/patologia , Células Epiteliais/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/epidemiologia , Cidade de Nova Iorque/epidemiologia , Lesões Pré-Cancerosas/diagnóstico , Lesões Pré-Cancerosas/epidemiologia , Porto Rico/epidemiologia , Fatores Sexuais , Neoplasias de Tecidos Moles/diagnóstico , Neoplasias de Tecidos Moles/epidemiologiaRESUMO
OBJECTIVES: We investigated whether oral cavity and pharyngeal cancer (OPC) incidence and mortality statistics among Hispanics in New York State differed from those among Hispanics in the United States as a whole. METHODS: OPC incidence and mortality statistics for 1996-2002 were obtained from the New York State Cancer Registry and compared with national statistics released by the Surveillance, Epidemiology, and End Results (SEER) program for the same period. RESULTS: Among Hispanic men, OPC incidence rates were approximately 75% and 89% higher in New York State and New York City, respectively, than national rates reported by the SEER program. No notable differences were identified among Hispanic women. Incidence rates among New York State Hispanic men were 16% higher than those of their non-Hispanic White counterparts. The difference was twice as high (32%) among Hispanic men in New York City. Mortality rates among both men and women exhibited patterns similar to the incidence patterns. CONCLUSIONS: Ethnoregional differences exist in the incidence and mortality rates of OPC in the United States. New York State Hispanic men exhibit much higher incidence and mortality rates than US Hispanics as reported by the SEER program.