HC Treatments Research Articles

Effect of growth rates on hormonal and pubertal status in Nellore heifers early weaned.

This study aimed to determine the effect of growth rates on the hormonal status and puberty onset. Forty-eight Nellore heifers were weaned at 3.0 ± 0.1 (means ± standard error of the mean) months old were blocked according to body weight at weaning (84 ± 2 kg) and randomly assigned to treatments. The treatments were arranged in 2 × 2 factorial according to the feeding program. The first program was high (H; 0.79 kg/day) or control (C; 0.45 kg/day) average daily gain (ADG) from 3rd to 7th month of age (growing phase I). The second program was also high (H; 0.70 kg/day) or control (C; 0.50 kg/day) ADG from the 7th month until puberty (growing phase II), resulting in four treatments: HH (n = 13), HC (n = 10), CH (n = 13), and CC (n = 12). To achieve desired gains, heifers in high ADG program were fed ad libitum dry matter intake (DMI), and the control group was offered around 50% of ad libitum DMI of high group. All heifers received a diet with similar composition. Puberty was assessed weekly by ultrasound examination, and the largest follicle diameter was evaluated every month. Blood samples were collected to quantify leptin, insulin growth factor-1 (IGF1) and luteinizing hormone (LH). At 7 months of age, heifers in high ADG were 35 kg heavier than the control. Heifers in the HH had greater DMI compared with CH in phase II. The puberty rate at 19 months old was greater in the HH treatment (84%) than in the CC (23%), but there was no difference between HC (60%) and CH (50%) treatments. Heifers from HH treatment had greater serum leptin concentration than others at 13 months old, and serum leptin was greater in HH compared with CH and CC at 18 months old. High heifers in phase I had greater serum IGF1 concentration than the control. In addition, HH heifers had a greater diameter of the largest follicle than CC. There was no interaction between phases and age in any variable relative to the LH profile. However, the heifers' age was the main factor that increased the frequency of LH pulse. In conclusion, increasing ADG was associated with greater ADG, serum leptin and IGF-1 concentration, and puberty onset; however, LH concentration was affected mainly by age of the animal. The increasing growth rate at younger age made heifers more efficient.

Influence of Biochar, Rock Phosphate, and Urea Nitrogen Fertilizer on Growth and Yield of Cucumber (Cucumis sativus) Grown in Standoff, Southern Alberta Greenhouse

Two trials were performed in greenhouse Standoff, Southern Alberta to investigate urea, rock phosphate, and biochar soil amendment on cucumber crops. The objective of the study was to confirm the effectiveness of rock phosphate and biochar with urea on greenhouse cucumber production. Two experiments were conducted in the Summer of 2020 and 2021 cropping seasons. The treatments applied in 2020 were the varying application of rock phosphate at 0 for control, 50 kg P ha-1 and 100 kg P ha-1 for phosphorus, and urea at 60 kg N ha-1 and 90 kg N ha-1 for nitrogen with their combinations N60 + P50, N90 + P100. In the 2021 cropping season, treatments applied were varying levels of Biochar (C) applied at a rate of 25 kg ha-1 (LC), 50 kg ha-1 (MC), and 100 kg ha-1 HC for Low, Medium, and High level, respectively, Urea (N) was applied at 30 kg N ha-1 and 60 kg N ha-1 (Low N and High N level, respectively) while rock phosphate (P) was applied at 25 kg P ha-1 and 50 kg P ha-1 (Low P and High P level, respectively) with their combinations. The seven treatments for each cropping season were replicated three times resulting in twenty-one experimental pots. The agronomical parameters data collected were subjected to one-way univariate analysis of variance using Duncan’s Multiple Range Test at 5% to separate the treatment means. The results of the experiment showed that High P and Low N treated pots influenced the growth of cucumber crop at 122 days after sowing (DAS) while High N, Low N, and Low N + Low P jointly favored the highest number of cucumbers on the vines than other treated pots at 82 DAS during the 2020 cropping season. However, all the treatments supported cucumber vine length except control and High P at 96 DAS while Low P + MC, High P, and High N+ P produced more fruits than control, High N and Low N + P + HC treatments at 96 DAS during the 2021 cropping season. It was observed that the addition of biochar in the 2021 cropping season influenced the growth and yield of cucumber when compared performance of cucumber crops in two growing seasons. This experiment advocates the use of biochar soil amendment in cucumber production.

Silver nanoparticles modify the hypothalamic-pituitary-interrenal axis and block cortisol response to an acute stress in zebrafish, Danio rerio.

The present study aimed at assessing the effects of exposure to silver nanoparticle (AgNP) and a subsequent acute stress on the expression of various genes involved in the hypothalamus-pituitary-interrenal (HPI) axis in zebrafish, Danio rerio. The fish were exposed to 0 (Control), 0.1 (LC), 0.4 (MC), and 1.2 (HC) mg Ag/L (as AgNP) over a 2-week period, followed by an acute air exposure stress. The whole body cortisol and the expression of selected genes in the fish brain and kidney were analyzed, before and after the acute stress. The results showed that AgNP increased basal cortisol levels and the expression of corticotropin releasing factor, prohormone convertase 1, pro-opiomelanocortin, and melanocortin 2 receptor; however, it suppressed/inhibited whole body cortisol, brain corticotropin releasing factor responses, pro-opiomelanocortin, and the kidney melanocortin 2 receptor responses to the acute stress. AgNP down-regulated the expression of the steroidogenic acute regulatory protein, but it intensified the gene expression in response to the acute stress. Before the acute stress, LC treatment exhibited an up-regulation in Cytochrome P450-11A-1 expression, but MC and HC treatments induced down-regulation. After the acute stress, the AgNP-exposed fish exhibited decreased Cytochrome P450-11A-1 expressions, compared with the Control. Exposure to AgNP significantly increased Cytochrome P450-11B expression. However, after the acute stress, LC treatment exhibited an up-regulation, but MC and HC treatments exhibited down-regulation in the Cytochrome P450-11B gene expression. In conclusion, AgNP suppressed cortisol response to stress, which appears to be a consequence of alterations in the HPI axis at the transcriptomic levels.

Responses of plant species to different aboveground removal treatments with implications for vegetation restoration in the Mu Us Sandland (Inner Mongolia)

It is generally assumed that plants can respond to varying degrees of physical damage by growth compensation via resprouting, and resprouting is a key functional trait in many species. Few studies have investigated how grass and shrub species distributed in moving dunes and semifixed dunes in semiarid areas respond to the combined effects of temperature and shoot removal. <em>Medicago sativa</em>, <em>Artemisia ordosica</em>, and <em>Artemisia sphaerocephala</em> plants were grown in a glasshouse for 8 weeks at air temperatures of 10/20°C, 12.5/22.5°C, 15/25°C, and 17.5/27.5°C (night/day) and were subjected to treatments of removing all leaves (LR), removing all leaves followed by cutting at half the plant height (HC), and removing all aboveground tissue (WC). The species, temperature, and damage extent had significant effects on the shoot number, leaf mass ratio, leaf area ratio and ratio of belowground to aboveground dry matter, and the species had a significant effect on the net assimilation rate, specific leaf area, and total biomass. The three species grew well under the HC and LR treatments, and high temperatures (15/25°C and 17.5/27.5°C) significantly promoted the regrowth of the three species. <em>Medicago sativa</em> grew faster than the two <em>Artemisia</em> species. <em>Medicago sativa</em> can be used for fertilizing or vegetation restoration in unimportant conservation areas, and the two <em>Artemisia</em> species can be effectively used for vegetation restoration in the Mu Us Sandland. Due to the low labor costs and the local climate conditions, plants should be clipped before the beginning of the main growing season (end of May or early June) to ensure rapid growth.

Metagenomic insights into effects of thiamine supplementation on ruminal non-methanogen archaea in high-concentrate diets feeding dairy cows

BackgroundOverfeeding of high-concentrate diet (HC) frequently leads to subacute ruminal acidosis (SARA) in modern dairy cows’ production. Thiamine supplementation has been confirmed to attenuate HC induced SARA by increasing ruminal pH and ratio of acetate to propionate, and decreasing rumen lactate, biogenic amines and lipopolysaccharide (LPS). The effects of thiamine supplementation in HC on rumen bacteria and fungi profile had been detected in our previous studies, however, effects of thiamine supplementation in HC on rumen non-methanogen archaea is still unclear. The objective of the present study was therefore to investigate the effects of thiamine supplementation on ruminal archaea, especially non-methanogens in HC induced SARA cows.ResultsHC feeding significantly decreased dry matter intake, milk production, milk fat content, ruminal pH and the concentrations of thiamine and acetate in rumen fluid compared with control diet (CON) (P < 0.05), while the concentrations of propionate and ammonia-nitrogen (NH3-N) were significantly increased compared with CON (P < 0.05). These changes caused by HC were inversed by thiamine supplementation (P < 0.05). The taxonomy results showed that ruminal archaea ranged from 0.37 to 0.47% of the whole microbiota. Four characterized phyla, a number of Candidatus archaea and almost 660 species were identified in the present study. In which Euryarchaeota occupied the largest proportion of the whole archaea. Furthermore, thiamine supplementation treatment significantly increased the relative abundance of non-methanogens compared with CON and HC treatments. Thaumarchaeota was increased in HC compared with CON. Thiamine supplementation significantly increased Crenarchaeota, Nanoarchaeota and the Candidatus phyla, however decreased Thaumarchaeota compared with HC treatment.ConclusionsHC feeding significantly decreased ruminal pH and increased the content of NH3-N which led to N loss and the increase of the relative abundance of Thaumarchaeota. Thiamine supplementation increased ruminal pH, improved the activity of ammonia utilizing bacteria, and decreased Thaumarchaeota abundance to reduce the ruminal NH3 content and finally reduced N loss. Overall, these findings contributed to the understanding of thiamine’s function in dairy cows and provided new strategies to improve dairy cows’ health under high-concentrate feeding regime.

Effects of ocean acidification and solar ultraviolet radiation on physiology and toxicity of dinoflagellate Karenia mikimotoi

A batch culture experiment was conducted to study the interactive effects of ocean acidification (OA) and solar ultraviolet radiation (UVR, 280–400 nm) on the harmful dinoflagellate Karenia mikimotoi. Cells were incubated in 7-days trials under four treatments. Physiological (growth, pigments, UVabc) and toxicity (hemolytic activity and its toxicity to zebrafish embryos) response variables were measured in four treatments, representing two factorial combinations of CO2 (400 and 1000 μatm) and solar irradiance (with or without UVR). Toxic species K. mikimotoi showed sustained growth in all treatments, and there was not statistically significant difference among four treatments. Cell pigment content decreased, but UVabc and hemolytic activity increased in all HC treatments and PAB conditions. The toxicity to zebrafish embryos of K. mikimotoi was not significantly different among four treatments. All HC and UVR conditions and the combinations of HC*UVR (HC-PAB) positively affected the UVabc, hemolytic activity in comparison to the LC*P (LC-P) treatment, and negatively affected the pigments. Ocean acidification (OA) was probably the main factor that affected the chlorophyll-a (Chl-a) and UVabc, but UVR was the main factor that affected the carotenoid (Caro) and hemolytic activity. There were no significant interactive effects of OA*UVR on growth, toxicity to zebrafish embryos. If these results are extrapolated to the natural environment, it can be hypothesized that this strain (DP-C32) of K. mikimotoi cells have the efficient mechanisms to endure the combination of ocean acidification and solar UVR. It is assumed that this toxic strain could form harmful bloom and enlarge the threatening to coastal communities, marine animals, even human health under future conditions.

Increased CO2 and iron availability effects on carbon assimilation and calcification on the formation of Emiliania huxleyi blooms in a coastal phytoplankton community

In the present work, we exposed a natural phytoplankton community to either present (390-μatm, LC) or future CO2 levels predicted for year-2100 (900-μatm, HC) combined with ambient (4.5 nmol L−1, −DFB) or high (12 nmol L−1, +DFB) dissolved iron (dFe) levels, during 25 days by using mesocosms. We report on changes in carbon assimilation processes (acquisition, fixation, and calcification) of the phytoplankton community due to increased dissolved CO2 and dFe and to the interaction of both factors. The isotopic disequilibrium assay results showed that inorganic carbon (Ci) acquisition by the community was unaffected by CO2 and Fe availability. The main Ci source for photosynthesis was HCO3− and external carbonic anhydrase activity was only detected at the beginning of the experiment, suggesting a relevant role for HCO3− transporters in the phytoplankton community developed in all treatments. However, there was a significant effect of both factors on particulate organic carbon (POC) content, particulate calcium production and carbon fixation rates. Increased dFe at LC conditions led to the highest values of carbon fixation and POC of all treatments, promoting a massive Emiliania huxleyi bloom. This response was not observed in the HC treatments. The latter indicates a negative impact of increased CO2 on the formation of E. huxleyi blooms, in agreement with the observed significant reduction in calcium production under HC. Our results suggest that ocean acidification can decrease primary production under iron-replete conditions in E. huxleyi blooming areas, affecting the biological carbon pump in coastal ecosystems.

Effects of DuPont Tyvek® non-woven material mulching on fruit quality and chlorophyll fluorescence in Wanzhou Rose Orange

To provide a theoretical basis for cultivation measures for alleviating the effects of weak daylight on citrus fruit quality, the effects of DuPont Tyvek® Non-Woven Material Mulching on Fruit Quality and Chlorophyll Fluorescence in Wanzhou Rose Orange [Citrus sinensis (L.) Osbeck cv Tarocco] was evaluated. At fructescence, soil surface of rose orange was applied full (FC) or half (HC) cover of DuPont Tyvek® non-woven materials, and relative light intensity, fruit quality, chlorophyll fluorescence, and other indexes were assessed. The experiment show that Tyvek® mulching significantly increased relative light intensity at different parts of the tree regardless of weather. Specifically, relative intensity of reflected light at the bottom was improved by more than 177.8%. In terms of fruit internal quality, the total soluble soiled (TSS) content of FC-treated trees was significantly increased compared with control values. However, titratable acid (TA) contents of HC-treated trees were significantly enhanced, delaying fruit ripening. Meanwhile, TA contents of FC-treated trees showed no significant changes, promoting fruit ripening. At the same time, FC and HC Tyvek® treatments significantly increased the final color index of fruits a/b. Both FC and HC treatments significantly improved peel uniformity and fresh coloring. Finally, HC and FC treatments significantly altered chlorophyll fluorescence transient and other leaf parameters; Fj, Vj, ABS/RC, RC/Cso and φDo in leaves of HC-treated trees were significantly increased, and ψo, φEo and Fv/Fo markedly decreased. Meanwhile, ABS/RC, RC/Cso and φDo in the FC group were significantly reduced, and ψo, φEo and Fv/Fo markedly increased, compared with control values. In conclusion, the FC method effectively decreases the effects of weak daylight on rose orange quality, and could improve its economic value.

Ocean acidification modulates expression of genes and physiological performance of a marine diatom.

Ocean Acidification (OA) is known to affect various aspects of physiological performances of diatoms, but little is known about the underlining molecular mechanisms involved. Here, we show that in the model diatom Phaeodactylum tricornutum, the expression of key genes associated with photosynthetic light harvesting as well as those encoding Rubisco, carbonic anhydrase, NADH dehydrogenase and nitrite reductase, are modulated by OA (1000 μatm, pHnbs 7.83). Growth and photosynthetic carbon fixation were enhanced by elevated CO2. OA treatment decreased the expression of β-carbonic anhydrase (β-ca), which functions in balancing intracellular carbonate chemistry and the CO2 concentrating mechanism (CCM). The expression of the genes encoding fucoxanthin chlorophyll a/c protein (lhcf type (fcp)), mitochondrial ATP synthase (mtATP), ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene (rbcl) and NADH dehydrogenase subunit 2 (ndh2), were down-regulated during the first four days (< 8 generations) after the cells were transferred from LC (cells grown under ambient air condition; 390 μatm; pHnbs 8.19) to OA conditions, with no significant difference between LC and HC treatments with the time elapsed. The expression of nitrite reductase (nir) was up-regulated by the OA treatment. Additionally, the genes for these proteins (NiR, FCP, mtATP synthase, β-CA) showed diel expression patterns. It appeared that the enhanced photosynthetic and growth rates under OA could be attributed to stimulated nitrogen assimilation, increased CO2 availability or saved energy from down-regulation of the CCM and consequently lowered cost of protein synthesis versus that of non-nitrogenous cell components.

Effects of different mechanical treatments on Quercus variabilis, Q. wutaishanica and Q. robur acorn germination

Abstract: Delayed and uneven germination of acorns has a negative effect on seedling quality and yield in seedlings. To address this issue, the effects of different mechanical treatments were studied, including a control (CK), removal of cup scar (RS), removal of pericarp (RP), removal of pericarp and 1/2 of the cotyledon (HC) and removal of pericarp and 2/3 cotyledon (TC), on the germination of Quercus variabilis, Q. wutaishanica and Q. robur acorns and pericarp thickness. The results showed that (1) RP and HC treatments significantly decreased root and shoot mean germination time, increased rooting and shooting germination percentage, and improved the root and shoot synchronization and vigor indexes of the three species’ acorns; (2) the acorns from the TC treatment significantly reduced root and shoot mean germination time and significantly induced the root and shoot synchronization index for all three species; and (3) the RS treatment significantly reduced the root and shoot mean germination time of the three species. Therefore, RP and HC treatments can effectively accelerate germination and regular seedling, which are important in the propagation of Q. variabilis, Q. wutaishanica and Q. robur seedlings. Even and quick germination help reduce acorn predation.

Effects of human contact and toys on the fear responses to humans of shelter-housed dogs

This study examined the effects of human contact and toys on fear responses to humans in small breed, shelter-housed dogs. Ninety dogs were assigned to one of three treatments: “control” (control), comprising routine husbandry performed by shelter staff; “human contact” (HC), where dogs additionally received 2min positive contact daily with an experimenter; or “human contact+toys” (HCT), where the additional human contact included the opportunity to interact with toys. Treatments were implemented daily from day 2 (second day in the shelter) until day 6. On day 7, the fear response towards the experimenter was assessed using salivary cortisol concentrations and a human avoidance test. The behavioural parameters measured were approach and withdrawal responses to the experimenter and time spent in each section of the pen while the experimenter was situated at each of three positions outside the pen: 2m (position 1) or 1m away from the pen gate (position 2) or crouched against the pen gate (position 3). On day 8, dogs were assessed by the shelter veterinarian for their suitability for adoption by the public. Treatment had no effect on salivary cortisol concentrations or the proportion of dogs selected for adoption. The results indicated that dogs in the HC and HCT treatments spent more time (P=0.024) at the front of the pen when the experimenter was at position 3 than control dogs (HC 8.8s, HCT 8.7s, control 6.6s from a possible 10s). For those dogs that were not at the front of the pen when the experimenter was in position 3, a higher (P<0.05) percentage of HCT dogs (100%) but not HC dogs (86%, P>0.05) approached the experimenter compared with control dogs (45%). A second experiment on another 40 dogs examined if dogs, based on their behaviour in the human avoidance test, discriminate between familiar and unfamiliar humans. All dogs received the HC protocol as in Experiment 1 and were observed in the human avoidance test, however, all dogs were tested twice, once with the ‘familiar’ experimenter and once with an ‘unfamiliar’ experimenter. There were no significant (P>0.05) familiarity or testing order effects, except that dogs approached the unfamiliar experimenter more (60%) than the familiar experimenter (29%) at position 2 (P<0.05). The results indicate that additional positive human contact other than that associated with routine husbandry reduced the behavioural fear response of dogs to humans, but did not affect the proportion of dogs selected for adoption. The results also indicate that the shelter dogs did not discriminate between familiar and unfamiliar humans, in the handling context used in this study, suggesting a degree of stimulus generalisation may occur.

Effects of Potassium Fertilizer on Water-Soluble Carbohydrate Content of Timothy (&amp;lt;i&amp;gt;Phleum pratense&amp;lt;/i&amp;gt; L.), Silage Fermentation, Nutritive Values, and Nutrient Intake

The objective of this study was to examine the effects of potassium fertilizer (standard (S) and high (H) levels) on water-soluble carbohydrate (WSC) content of timothy (Phleum pratense L.), silage fermentation, nutritive values, and nutrient intake. The silage treatments were as follows: S level without inoculant (SC), S level plus inoculant (SI), H level without inoculant (HC), and H level plus inoculant (HI). The K content was increased by 14.5% in timothy grown with the H level compared with the S level. The WSC contents of the S and H treatments were 75.9 and 66.1 g·kg-1 dry matter (DM), respectively. The silage fermentation quality was low with both SC and HC treatments. The addition of inoculant significantly improved the fermentation quality in SI and HI treatments. The addition increased the DM and organic matter digestibilities of silage. The total digestible nutrient (TDN) content of silage was highest with the HI treatment. The DM, TDN, and digestible energy intakes with the SI and HI treatments were improved compared with the SC and HC treatments, respectively. This study demonstrated negligible effects of K fertilizer levels and significant effects of the lactic acid bacteria inoculant on the fermentation quality, nutritive values, and feed intake of silage.

Influence of Herbicide and Soil Amendments on Soil Nitrogen Dynamics, Microbial Biomass, and Crop Yield in Tropical Dryland Agroecosystems

Nitrogen (N) dynamics is the key factor for designing management strategies to achieve sustained crop productivity. A 2‐yr field experiment was performed to examine the influence of herbicide (butachlor [2‐chloro 2′6′ diethyl‐n‐butoxy‐methylacetanilide]; HC) alone or in combination with soil amendments on N dynamics involving N mineralization rate (Nmin), inorganic N pool, N uptake (Nup) by plants, soil microbial biomass N, and crop yield in tropical dryland agroecosystems. The Nmin rate showed distinct seasonal patterns which decreased from rice period to summer fallow except herbicide + animal manure (farmyard manure; HC + AM) and herbicide + crop residue (wheat [Triticum aestivum L.] straw; HC + CR) treatments.The annual rate of Nmin, inorganic N pool, and crop yield were higher in HC + AM, herbicide + chemical fertilizer (NPK; HC + CF), herbicide + green manure {dhaincha [Sesbania aculeata (Willd.) Pers.] shoots; HC + GM} while comparable in HC + CR and HC treatments relative to control (CO). Soil moisture content better predicted variation in Nmin rate compared to soil temperature. Plant Nup and crop yield relative to CO was higher in HC + CF, HC + GM, and HC + AM, comparable in HC + CR while lower in the HC treatment. Annual Nmin rate explained a significant part of variations in annual soil microbial biomass N, inorganic N pool, plant Nup, and crop yield. Results indicate that combined application of HC + AM result in relatively sustained availability of inorganic N and higher crop yield throughout the annual cycle.

Effects of fermented garlic powder supplementation on growth performance, blood characteristics and meat quality in finishing pigs fed low-nutrient-density diets

This study was conducted to evaluate the different levels of fermented garlic powder supplemented in low-nutrient-density diet on growth performance, blood characteristics and meat quality in finishing pigs. A total of 96 [(Landrace×Yorkshire)×Duroc] pigs with an initial body weight (BW) of 55.80±1.81kg were used in a 12-week experiment. Pigs were randomly allotted to 1 of 4 treatments according to their sex and BW (6 replicates, 4 pigs per pen, 2 gilts and 2 barrows). Dietary treatments included: 1, HC (negative control; high-nutrient-density diet); 2, LC (positive control; low-nutrient-density diet); 3, LG2 (LC+2g/kg fermented garlic powder) and 4, LG4 (LC+4g/kg fermented garlic powder). The pigs were subjected to a 2-period feeding program consisting of early finisher (0 to 6weeks) and late finisher (6 to 12weeks) periods. The average daily gain (ADG) in LG2 treatment was higher (P<0.05) than other groups during 0 to 6weeks. The average daily feed intake (ADFI) was greater (P<0.05) in the LG2 group than that in HC and LG4 diets. During 6 to 12weeks, pigs fed diets including fermented garlic powder increased ADG greatly (P<0.05) compared to HC and LC groups. Furthermore LG2 treatment led to a higher ADFI (P<0.05) than LC diet. Gain/feed (G/F) ratio was improved (P<0.05) when pigs fed LG4 diet compared to those fed HC or LC. Pigs fed LG2 diet increased ADG (P<0.05) significantly when compared with those fed HC or LC diets over the trial. Additionally, LG2 treatment had a higher ADFI (P<0.05) than LC and LC4 treatments. In sensory evaluation, pigs fed garlic supplementation showed a higher marbling score (P<0.05) than that in HC and LC treatments. Firmness score was greater (P<0.05) in LG2 treatment than that in other treatments. However, no other difference was observed in pH, meat color and drip loss during the experiment period. These results indicated that fermented garlic powder supplementation at the level of 2g/kg could improve growth performance and concomitantly meat marbling and firmness score.

Effect of limit feeding high- and low-concentrate diets with Saccharomyces cerevisiae on digestibility and on dairy heifer growth and first-lactation performance

Growth and digestibility were examined for heifers limit fed high- (HC; 60%) and low-concentrate (LC; 20%) diets with or without yeast culture (YC) addition in 2 experiments. A third experiment was undertaken to monitor first-lactation production of heifers limit fed HC or LC diets. In experiment 1, 32 Holstein heifers were individually fed at controlled intakes for 133 d to maintain a targeted average daily gain of 0.80kg/d for all 4 treatments [HC; LC with and without Saccharomyces cerevisiae; Yea-Sacc1026 (Alltech Inc., Nicholasville, KY), 1 g/kg as fed]. Targeted average daily gain was achieved for all treatments during the individual feeding period (0.80±0.01kg/d). Average dry matter intake needed to maintain constant gain was slightly reduced for HC and YC treatments. Reduced dry matter intake and similar targeted average daily gain resulted in a tendency for improved feed efficiency of HC-fed heifers. Skeletal measurements and targeted average daily gain were not affected by concentrate level or YC. The objective of experiment 2 was to elucidate effects of concentrate level and YC on nutrient digestibility. Four young (284.35±4.51 d) and 4 older (410.28±2.14 d) heifers were allocated to the 4 treatments used in experiment 1. Heifers fed the HC diet had increased dry matter digestibility (75.67 vs.72.96±0.72%), and YC addition increased dry matter digestibility (74.97 vs. 73.65±0.71%). Intake of N and apparent N digestibility were similar for all treatments. High-concentrate diets and YC addition decreased wet and dry matter output of feces. Urine excretion was not different; therefore, total manure output was lower for HC-fed heifers as compared with LC-fed heifers. Results suggest that HC diets can improve feed efficiency without affecting growth when limit fed to dairy heifers. Yeast culture increased dry matter digestibility in HC- and LC-fed heifers; HC diets were more digestible and reduced fecal output, with YC enhancing this effect. In experiment 3, heifers from experiment 1 were group fed the same diets (HC or LC) without YC until parturition, and milk production was measured through 154 d of lactation. Group-fed average daily gain was not different between treatments (HC = 1.11 vs. LC = 1.04kg/d, SE = ±0.06kg/d). Heifers fed the HC and LC diets calved at 23.50 and 23.79±0.50 mo, respectively. Peak milk was lower and there was a tendency for reduced daily milk and protein yield for primiparous cows fed HC diets from 8 mo of age to the dry/prefresh period (long term), but predicted yields of milk and components were similar in the first 154 d of lactation.

A common garden experiment with larval Northeast Arctic and Norwegian coastal cod cohorts in replicated mesocosms

Abstract A replicated mesocosm experiment was carried out to evaluate differential effects of feeding conditions for larval Northeast Arctic (NA) cod and Norwegian coastal (NC) cod. The two populations were (1) reared together with a 6-day older NA cohort (mixed) in high (HC) and low prey concentration (LC; 2000 and 200 prey/L initially), and (2) reared separately in HC treatments (non-mixed) to be able to evaluate both the effect of feeding conditions and possible effects of size interaction within mesocosms. The larvae were fed natural zooplankton, and the two stocks were identified in the mixed mesocosms by otolith marking. NA larvae hatched at a larger size, had higher growth rates, and survived better than NC larvae in both mixed and non-mixed mesocosms in the HC treatment. The second cohort clearly survived better in the non-mixed than in the mixed mesocosms, indicating the presence of an interaction effect before cannibalism could occur. We found a significant higher weight-at-length between NC and NA larvae (

Dietary l-Carnitine Affects Periparturient Nutrient Metabolism and Lactation in Multiparous Cows

The objectives of this study were to determine the effects of dietary l-carnitine supplementation on liver lipid accumulation, hepatic nutrient metabolism, and lactation in multiparous cows during the periparturient period. Cows were assigned to treatments at d −25 relative to expected calving date and remained on the experiment until 56 d in milk. Treatments were 4 amounts of supplemental dietary carnitine: control (0 g/d of l-carnitine; n = 14); low carnitine (LC, 6 g/d; n = 11); medium carnitine (MC, 50 g/d; n = 12); and high carnitine (HC, 100 g/d; n = 12). Carnitine was supplied by mixing a feed-grade carnitine supplement with 113.5g of ground corn and 113.5g of dried molasses, which was then fed twice daily as a topdress to achieve desired daily carnitine intakes. Carnitine supplementation began on d −14 relative to expected calving and continued until 21 d in milk. Liver and muscle carnitine concentrations were markedly increased by MC and HC treatments. Milk carnitine concentrations were elevated by all amounts of carnitine supplementation, but were greater for MC and HC than for LC during wk 2 of lactation. Dry matter intake and milk yield were decreased by the HC treatment. The MC and HC treatments increased milk fat concentration, although milk fat yield was unaffected. All carnitine treatments decreased liver total lipid and triacylglycerol accumulation on d 10 after calving. In addition, carnitine-supplemented cows had higher liver glycogen during early lactation. In general, carnitine supplementation increased in vitro palmitate β-oxidation by liver slices, with MC and HC treatments affecting in vitro palmitate metabolism more potently than did LC. In vitro conversion of Ala to glucose by liver slices was increased by carnitine supplementation independent of dose. The concentration of nonesterified fatty acids in serum was not affected by carnitine. As a result of greater hepatic fatty acid β-oxidation, plasma β-hydroxybutyric acid was higher for the MC and HC treatments. Serum insulin was greater for all carnitine treatments, although plasma glucose was unaffected. Plasma urea N was lower and plasma total protein was higher for the MC and HC treatments. By decreasing liver lipid accumulation and stimulating hepatic glucose output, carnitine supplementation might improve glucose status and diminish the risk of developing metabolic disorders during early lactation.

Effect of pasture allowance and supplementation with maize silage and concentrates differing in crude protein concentration on milk production and nitrogen excretion by dairy cows

Sixty cows (40 multiparous and 20 primiparous) averaging 140 days in milk (DIM) were assigned to five treatments to evaluate the effect of pasture allowance and supplements of a) maize silage b) high crude protein concentrate and, c) low crude protein concentrate on milk production and nitrogen (N) excretion. Two of the treatments (HG and LG) were offered herbage only (allowances of 20 and 15 kg dry matter (DM) per cow/day, respectively) while the remaining three treatments were offered a herbage allowance of 15 kg DM per cow/day plus 4 kg DM per cow/day of maize silage (M), a high CP concentrate (CP concentration of 194 g/kg DM) (HC), or citrus pulp (CP concentration of 69 g/kg DM) (LC). Total DM intake (DMI) was similar for HG, M, HC, and LC but was lower for LG (15.2 kg DM per cow/day) than HC (17.4 kg DM per cow/day). The reduction in pasture DMI per kg of supplement DM ingested was 0.44, 0.45, and 0.54 kg for cows offered maize silage, high CP concentrate, and low CP concentrate, respectively. Milk yield was greater for the supplemented treatments (23.7–24.7 kg/day) than for LG (20.7 kg/day) but not for HG (23.2 kg/day). Milk fat concentration was greater for HC (35.3 g/kg) than for HG, M, and LC but not greater than LG, while milk protein concentration was greater for HG (34.8 g/kg) than for LG and HC but not greater than M and LC. The greatest levels of N and PDIN intake were recorded for HG (662 and 2502 g/day) and HC (654 and 2506 g/day) which were greater than LC but not greater than LG and M. Treatment HC recorded the highest PDIE intake (1743 g/day) which was greater than LG, M and LC but not greater than HG. Output of N in milk was greater on HC (134 g/day) than on LG but was not greater than on HG, M, and LC. Faecal N excretion was greater on HG (171 g/day) than on all other treatments while estimated urinary N excretion was greater on HG and HC than LC (320 g/day). Treatment LC had a higher proportion of N output in milk (0.23) than treatment LG but not higher than HG, M and HC treatments. Urinary N expressed as a proportion of total N excretion was lower for HG (0.68) than all other treatments. The results of this study show that there is a large response in milk production to supplementing cows on a restricted grass allowance and that cows offered low CP supplements had similar levels of production to those offered high CP supplements. Nitrogen utilisation was improved by offering supplements of lower CP content.

Effect of timing of feeding a high-concentrate diet on growth and attainment of puberty in early-weaned heifers1

Precocious puberty (<300 d of age) can be successfully induced in a majority of heifers with early weaning and continuous feeding of a high-concentrate diet. The objective of this experiment was to determine the relative effects of timing of feeding a high-concentrate diet on age at puberty in early-weaned heifers. Sixty crossbred Angus and Simmental heifer calves were weaned at 112 +/- 2 d of age and 155 +/- 3 kg of BW and were fed a receiving diet for 2 wk. Heifers were blocked by age and BW, and assigned randomly to receive a high-concentrate (60% corn; H) or control (30% corn; C) diet during phase 1 (mean age 126 to 196 d) and H or C during phase 2 (mean age 196 to 402 d), resulting in 4 treatments (HH, n = 15; HC, n = 15; CH, n = 15; and CC, n = 15). Blood samples were collected weekly beginning at a mean age of 175 d and assayed for progesterone concentration to determine age at puberty. After 56 d on the experimental diets, BW of heifers fed the H diet during phase 1 were greater (P < 0.05) than those of heifers fed the C diet (mean age of 182 d; treatment x mean age, P < 0.01). After 70 d on the new diets (mean age of 266 d), heifers fed the H diet during phase 2 reached heavier BW (P < 0.05) than heifers fed the C diet, when compared within phase 1 diet groups (HH > HC; CH > CC). Body weights in HC and CH treatments differed from a mean age of 169 through 238 d, after which BW did not differ between these treatments. The ADG over the entire experimental period was greatest for the HH treatment (1.2 +/- 0.04 kg/d; P < 0.05), followed by the HC and CH treatments (1.0 +/- 0.03 and 1.0 +/- 0.02 kg/d, respectively), which were not different, and the CC treatment gained the least (0.7 +/- 0.04 kg/d; P < 0.05). Precocious puberty occurred in 67, 47, 47, and 20% of heifers in the HH, HC, CH, and CC treatments, respectively (HH > CC; P < 0.05). Mean age at puberty for the HH and HC treatments (271 +/- 17 and 283 +/- 17 d of age, respectively) was earlier (P < 0.05) than for the CC treatment (331 +/- 11 d of age). Age at puberty in the CH treatment (304 +/- 13 d of age) was intermediate to and not different from the other treatments. Heifers fed the H diet during phase 1 attained puberty earlier (P < 0.05) than heifers fed the C diet during phase 1. In conclusion, increasing dietary energy intake in early-weaned heifers, through feeding a high-concentrate diet from 126 to 196 d of age, decreased age at puberty regardless of the diet fed after 196 d of age.

Follicular Fluid and Cumulus Cells Synergistically Improve Mouse Early Embryo Development In Vitro

The development of preimplantation mammalian embryos in vitro is less than optimal. Follicular fluid and cumulus cells have both been used independently, to improve preimplantation embryo quality in culture. This study was undertaken to evaluate the influence of a cumulus cell monolayer in human follicular fluid on mouse early embryo development in vitro. One-cell embryos were obtained from NMRI mice after superovulation with eCG and hCG. Cumulus cells were prepared from mouse egg-cumulus mass. These cells were separated from red blood cells using a Percoll gradient. Follicular fluid was collected from patients undergoing an IVF program during oocyte pick-up. The cumulus cell monolayer was prepared in follicular fluid (FC) and Ham's F10 (HC). Mouse one-cell embryos were cultured in FC, HC, Ham's F10 (HF) and follicular fluid (FF) for 120 h. Only 10.5% of embryos passed the two-cell block in HF. However, the proportions of embryos passing the two-cell block were 23.1%, 21.4% and 68.5% in FF, HC, and FC treatments, respectively; which were significantly different from HF (p<0.05). The differences between FC and the two other treatments were also significant (p<0.001). In FC, 33.7% of one-cell embryos continued to grow to the blastocyst stage whereas only 2.1% and 1.9% of one-cell embryos in FF and HC reached this stage and no embryos developed to blastocyst in HF. The proportion of blastocysts in FC was significantly higher than all other treatments (p<0.001). It can be concluded that follicular fluid and cumulus cells in monolayer form synergistically improve the early embryo culture condition.