Growth-related hormones in plasma of bulls, steers and heifers given food with two different energy levels

Genomic signatures for drylands adaptation at gene-rich regions in African zebu cattle

Background

Indigenous Sudanese cattle are mainly indicine/zebu (humped) type. They thrive in the harshest dryland environments characterised by high temperatures, long seasonal dry periods, nutritional shortages, and vector disease challenges. Here, we sequenced 60 indigenous Sudanese cattle from six indigenous breeds and analysed the data using three genomic scan approaches to unravel cattle adaptation to the African dryland region.

Results

We identified a set of gene-rich selective sweep regions, detected mostly on chromosomes 5, 7 and 19, shared across African and Gir zebu. These include genes involved in immune response, body size and conformation, and heat stress response. We also identified selective sweep regions unique to Sudanese zebu. Of these, a 250 kb selective sweep on chromosome 16 spans seven genes, including PLCH2, PEX10, PRKCZ, and SKI, which are involved in alternative adaptive metabolic strategies of insulin signalling, glucose homeostasis, and fat metabolism.

Conclusions

Our results suggest that environmental adaptation may involve recent and ancient selection at gene-rich regions, which might be under a common regulatory genetic control, in zebu cattle.

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Sudanese cattle thrive in the harshest environments of the African drylands.

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Bos indicus shared selected genes are involved in immune response, conformation, and heat stress response.

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Sudanese zebu-specific sweep includes genes involved in alternative adaptive metabolic strategies of insulin signalling, glucose homeostasis, and fat metabolism.

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Environmental adaptation in zebu cattle may involve recent and ancient selection at gene-rich regions, which might be under a common regulatory genetic control.

Effects of dietary inclusion of Moringa oleifera leaf meal on nutrient digestibility, rumen fermentation, ruminal enzyme activities and growth performance of buffalo calves

This study was conducted to investigate the impact of dietary inclusion of Moringa oleifera leaf meal (MLM) as a substitution for soybean meal on nutrient digestibility, rumen fermentation, rumen enzyme activity, blood metabolites, growth-related hormones, and growth performance of buffalo calves. Thirty buffalo calves eight to nine months of age with an average body weight of approximately 153.7 ± 0.97 kg were randomly distributed through three dietary treatments (ten calves/treatment). MLM inclusion rates were 15% (M15) and 20% (M20), replacing soybean meal by 50 and 75% in the concentrate mixture, respectively. The results indicated that, digestibility of dry matter, organic matter (OM), and crude fiber (CF) increased significantly (p < 0.05) with MLM inclusion, while the digestibility of crude protein (CP) and ether extract (EE) reduced significantly (p < 0.05) with MLM addition. Dietary supplementation with MLM significantly affected (p < 0.001) rumen fermentation by reducing ruminal enzymes, ruminal ammonia-N, total protozoa, and acetate/propionate ratio and increasing acetic, propionic, and butyric acids and total volatile fatty acid concentrations (p < 0.001). Furthermore, dietary inclusion of 15% MLM significantly improved (p < 0.001) final body weight, dry matter intake of feed, daily weight gain, feed conversion efficiency, blood metabolites, and plasma insulin growth factor-I (IGF-I). It can be concluded that MLM is a multi-purpose protein supplement that provides some nutritional and therapeutic advantages when replacing 50% of soybean meal. Dietary supplementation of 15% MLM improved rumen fermentation, growth performance, blood metabolites, plasma IGF-I and mitigated ammonia and methane without any adverse effects in growing buffalo calves.

Effects of immunocastration performed at two live weights on the growth physiology, temperament and testicular development of feral beef bulls

The aim of this study was to examine the effect of administering an anti-gonadotropin-releasing hormone vaccine (Improvac^® , developed for pigs) on the performance, temperament, testicular development, and hormone and metabolite profiles of feral bulls (Bos taurus) vaccinated at two different live weights (LW). In all, 16 Serrana de Teruel animals were involved in this 2 x 2 factorial design using the factors LW (LIGHT vs. HEAVY) and vaccine treatment (control, C vs. vaccinated, VA). All animals received the same diet (ad libitum concentrate plus straw) over a 164-day fattening period. Temperament was assessed using chute and flight speed tests. Testicular diameter and subcutaneous fat thickness were recorded. Testosterone, IGF-1, urea, NEFA, and creatinine profiles were analyzed. Bull weight gain was reduced in VA compared to C animals, regardless of the initial LW. The vaccine did not affect the temperament tests, subcutaneous fat thickness or NEFA and creatinine concentrations and had minor effects on linear body measures. The vaccine inhibited testicular growth, reduced plasma testosterone to residual levels, and increased urea concentrations. LIGHT-C animals exhibited increased mean plasma IGF-1 concentrations compared to LIGHT-VA animals. In conclusion, vaccination reduced bull growth and sexual development irrespective of LW at immunization.

Effects of incremental changes in forage: concentrate ratio on plasma hormone and metabolite concentrations and products of rumen fermentation in fattening beef steers

As part of an investigation of factors responsible for a previously reported lower efficiency of carcass lean gain in steers offered grass silage diets, 16 Simmental × Friesian steers (515 (s.e. 6·4) kg) were offered perennial ryegrass silage ad libitum (C0) or silage plus rolled barley at 200 (C20), 400 (C40) or 600 (C60) g/kg total diet dry matter (DM). Barley-supplemented diets were intake-restricted to provide equal DM and metabolizable energy (ME) intakes to those offered C0. Eight steers were selected at random to determine the ME contents of the diets by open-circuit respiration calorimetry. The other eight steers were offered the same diets and were blood-sampled at 20- to 60-min intervals, for 10 h, to monitor changes in the concentrations of a number of nutritionally related plasma metabolites and hormones. Estimated ME intakes in these steers were 85·7, 83·1, 84·4 and 86·2 (s.e. 0·91) MJ/day from diets C0, C20, C40 and C60 respectively. Rumen-fistulated Hereford × Friesian steers provided 24-h rumen data for the same diets offered at equal amounts of ME per kg metabolic live weight.

Mean 24-h plasma concentrations of insulin and insulin-like growth factor 1 (IGF-1) were linearly and positively related (P < 0·01 and P < 0·001 respectively) and glucagon quadratically related (P < 0·05) to the proportion of barley in the diet. Plasma insulin increased after feeding on all diets but concentrations on diets C40 and C60 were significantly higher than those on C0 and C20 at all post-feeding sampling times up to 9 h after feeding. Plasma IGF-1 concentrations increased above pre-feeding levels following feeding of the higher barley diets (C40 and C60; P = 0·053) but remained unchanged in steers offered C0 and C20. Mean plasma concentrations of glucose were unaffected by diet but those of β-hydroxybutyrate (BOHB) and urea were positively and negatively related respectively (both P < 0·001) to the proportion of barley in the diet. Plasma BOHB and urea concentrations also changed with time after feeding (P < 0·001). Amongst the rumen parameters measured (pH; ammonia and volatile fatty acid concentrations and proportions) only the mean 24-h concentrations and proportions of butyrate were positively related to the proportion of barley in the diet (P = 0·051 and P < 0·05 respectively). All rumen parameters were affected by time after feeding (acetate, P < 0·01; others, P < 0·001) but there was no interaction between treatment and time for any parameter.

Insulin secretion and signaling in response to dietary restriction and subsequent re-alimentation in cattle

The objectives of this study were to examine systemic insulin response to a glucose tolerance test (GTT) and transcript abundance of genes of the insulin signaling pathway in skeletal muscle, during both dietary restriction and re-alimentation-induced compensatory growth. Holstein Friesian bulls were blocked to one of two groups: 1) restricted feed allowance for 125 days (period 1) (RES, n = 15) followed by ad libitum feeding for 55 days (period 2) or 2) ad libitum access to feed throughout (periods 1 and 2) (ADLIB, n = 15). On days 90 and 36 of periods 1 and 2, respectively, a GTT was performed. M. longissimus dorsi biopsies were harvested from all bulls on days 120 and 15 of periods 1 and 2, respectively, and RNA-Seq analysis was performed. RES displayed a lower growth rate during period 1 (RES: 0.6 kg/day, ADLIB: 1.9 kg/day; P < 0.001), subsequently gaining more during re-alimentation (RES: 2.5 kg/day, ADLIB: 1.4 kg/day; P < 0.001). Systemic insulin response to glucose administration was lower in RES in period 1 (P < 0.001) with no difference observed during period 2. The insulin signaling pathway in M. longissimus dorsi was enriched (P < 0.05) in response to dietary restriction but not during re-alimentation (P > 0.05). Genes differentially expressed in the insulin signaling pathway suggested a greater sensitivity to insulin in skeletal muscle, with pleiotropic effects of insulin signaling interrupted during dietary restriction. Collectively, these results indicate increased sensitivity to glucose clearance and skeletal muscle insulin signaling during dietary restriction; however, no overall role for insulin was apparent in expressing compensatory growth.

Growth and carcass characteristics of heavy slaughter weight lambs: effects of sire breed and sex of lamb and relationships to serum metabolites and IGF-1

Texel (T) and Suffolk (S) sired ram, wether and ewe lambs (no = 180) were kept at grass with their dams until weaned at 20 weeks and then taken to slaughter weights of 40, 44 and 48 kg, also at grass. Sex type, but not sire breed, affected lamb growth rate (rams 293, wethers 253, ewes 224 g/day; P < 0·001). Both T and S ewe lambs were fatter at slaughter in all fat depots compared with their ram and wether siblings such that rams could be slaughtered at a calculated 7·7 kg greater live weight than ewes at equal carcass fat cover. T carcasses were greater than S carcasses in eye-muscle area (793 v. 732 mm2; P < 0·001) and killing-out proportion (481 v. 476 g/kg; P < 0·05) but not in any fat measurement. Slaughter weight influenced killing-out proportion (P < 0·001) and all fat measurements (P < 0·01) but did not significantly affect eye-muscle area.

Mean serum insulin-like growth factor-1 (IGF-1) concentrations (μig/l), determined during weeks 8,11, 14, 17 and 20 in a balanced subset of 84 lambs, were higher in T than in S lambs (P < 0·05), in singles than in twins (P < 0·01; rams and wethers only) and in rams than in either wethers or ewes (P < 0·001). Mean serum IGF-1 concentration decreased between week 8 and week 20 with a greater rate of decline in singles than in twins (P < 0·001). IGF-1 was more strongly correlated with live weight at 8 weeks (r = 0·629; P< 0·001) than at 20 weeks (r = 0·293; P < 0·05). Mean IGF-1 (weeks 8 to 20) was correlated with rate of live-weight change (r = 0·576; P < 0·001). Significant differences for T and S lambs were found in the relationships between mean serum IGF-1 (weeks 8 to 20) and daily live-weight gain (weeks 8 to 20) and between mean IGF-1 and eye-muscle area at slaughter. Metabolite concentrations differed little between sire breeds and not at all between sex types.