Tannin supplementation modulates the composition and function of ruminal microbiome in lambs infected with gastrointestinal nematodes.

This study was carried out to evaluate the effects of tannin supplementation on ruminal microbiota of sixteen lambs infected and non-infected with Haemonchus contortus and Trichostrongylus colubriformis. Animals were fed with hay, concentrate and supplemented with Acacia mearnsii (A. mearnsii). The animals were divided into four treatments: two control groups without infection, either receiving A. mearnsii (C+) or not (C-), and two infected groups, one with A. mearnsii (I+) and another without A. mearnsii (I-). Ruminal short-chain fatty acids (SCFA) and metagenome sequencing of ruminal microbiota were used to evaluate the effect of tannin and infection on ruminal microbiome. For SCFA, differences were observed only with A. mearnsii. Total SCFA and acetate molar percentage were decreased in C+ and I+ (P<0.05). Butyrate, valerate and isovalerate were higher in lambs that received A. mearnsii in the diet (P<0.05). The infection changed the microbiome structure and decreased the abundance of butyrate-producing microorganisms. In addition, A. mearnsii supplementation also affected the structure the microbial community, increasing the diversity and abundance of the butyrate-producing and probiotics bacteria, amino acid metabolic pathways, purine, pyrimidine and sphingolipid metabolism. Together, our findings indicate that A. mearnsii supplementation modulates important groups related to nitrogen, amino acid, purine and pyrimidine metabolism, in rumen microbiome, affected by gastrointestinal nematodes infection in lambs.

Effects of Maternal Dietary Cottonseed on the Profile of Minerals in the Testes of the Lamb.

The use of cotton co-products in animal feed is restricted by the presence of gossypol, which is a toxic and highly reactive molecule of complex minerals. In mammals, part of the offspring phenotype is influenced by dam nutrition. The aim of this study was to investigate the effect of ewe diet, with and without cottonseed (gossypol), on the testicular development of lambs from birth to weaning through the assessment of lamb live weight (LW), macro and histological morphology of testes, and mass fraction of chemical elements by neutron activation analysis (NAA) and microprobe X-ray fluorescence spectroscopy, as well as the multielement distribution map in the testes. Eighteen lambs were used with an average LW at birth of 4 ± 1.0 kg. All lambs were offspring of Santa Inês ewes, fed on ration either with or without cottonseed during mating, gestation, and lactation, thus forming two treatments: control group (C) without cottonseed and treatment group with cottonseed (G). The animals were weighed from birth to 60 days of age, at fortnightly intervals. At 60 days of age, the lambs were orchidectomized to collect their testes for macroscopy, histological, neutron activation, and X-ray fluorescence analysis. Besides dry matter (DM), protein, ether extract (EE), calcium (Ca), and potassium (K) were higher in the ewe milk from the C group compared with the G group (P < 0.05). Lambs from the C group showed higher LW from 45 days onwards, as well as higher average daily gain when compared with the G group (P < 0.05). They also presented higher testicular weight, volume, length, width, as well as tubule and lumen diameters compared with lambs from the G treatment (P < 0.05). Multielementary NAA revealed higher mass fractions of rubidium (Rb), selenium (Se), and cesium (Cs) in the testes of lambs from the C group when compared with the G group, while G showed higher zinc (Zn) content (P < 0.05). No differences between treatments were found for element levels and distribution using X-ray fluorescence microanalysis (P > 0.05). In conclusion, the maternal cottonseed diet compromised performance and testes development of the lambs and reduce the content of Se in the testes.

Fatty acid profile and carcass characteristics in castrated and uncastrated hair lambs.

The aim of this study was to investigate the effects of castration on carcass characteristics and fatty acid profile of visceral fat and meat from lambs. Eighteen six-month-old Santa Inês male lambs (18.9 ± 2.4 kg of body weight (BW)) were used. Animals were assigned to two treatments according to their sexual condition: uncastrated (U) or castrated (C). During a 98-day experimental period, animals were kept on an Andropogon gayanus grass pasture area of 1 ha and supplemented with 200 g/animal/day of concentrate mixture. Water and mineral salt were available ad libitum. The lambs were weighed fortnightly, and at the last day of the trial, they were slaughtered for evaluation of carcass characteristics and fatty acids profile of perirenal fat and longissimus lumborum muscle samples. Castrated lambs showed higher BW than U during most part of the experiment (p < 0.05). Fat deposition was higher in C lambs as evidenced by their increased carcass fat cover. Meat from U lambs showed lower content of C16:0 and higher polyunsaturated fatty acids (PUFA) (p < 0.05) than that from C (U, 14.3 and C, 10.5%). Conjugated linoleic acid (CLA) content was not affected by castration (p > 0.05) (U, 0.74 and C, 0.76%). The cis-9, cis-12 C18:2n-6 (U, 10.6 and C, 6.86%) fatty acid and the PUFA:SFA (saturated fatty acids) ratio (U, 0.36 and C, 0.25) were higher in the muscle of U lambs (p < 0.05), indicating that the meat from U animals may provide more benefits to human health than that of C.