Effects of Weaning Age at 21 and 28 Days on Growth Performance, Intestinal Morphology and Redox Status in Piglets

The study objective was to assess effects of different weaning ages on growth performance, intestinal morphology and redox status in Duroc × Landrace × Large White piglets (n = 96) fed diets without antibiotic growth promoters. Piglets were selected from 24 litters based on similar body weight at 14 d of age. All piglets were allocated to two groups in a completely random design with six replicates and eight pigs per replicate (four barrows and four gilts), which were weaned at 21 (n = 48; BW = 6.87 ± 0.33 kg) and 28 (n = 48; BW = 8.49 ± 0.41 kg) days of age. After weaning, pigs were fed a corn–soybean meal-based diet. Average daily gain (ADG), average daily feed intake (ADFI), feed conversion (F:G), diarrhea incidence, gastrointestinal pH, intestinal morphology and redox status were determined. Pigs weaned at 28 d displayed increased ADG from d 8 to 14 (p < 0.01) compared with pigs weaned at 21 d. Pigs weaned at 28 d had a higher ADFI from d 0 to 7 (p < 0.01), d 8 to 14 (p < 0.01), d 15 to 28 (p < 0.05) and during the entire experimental period (p < 0.01) compared with pigs weaned at 21 d. Pigs weaned at 21 d had an improved F:G from d 15 to 28 (p < 0.05) compared with pigs weaned at 28 d. Pigs weaned at 28 d had decreased diarrhea incidence from d 8 to 14 (p < 0.01) and the entire experimental period (p < 0.01) compared with pigs weaned at 21 d. On d 28, the pH of the stomach contents in pigs weaned at 21 d was significantly higher compared with pigs weaned at 28 d (p < 0.01). On d 14, the morphology of the duodenum, jejunum and ileum in pigs weaned at 28 d was improved compared with pigs weaned at 21 d. During the experiment period, the antioxidant abilities of pigs weaned at 28 d of the heart, liver, kidney, intestinal and serum were better than pigs weaned at 21 d. In conclusion, intestinal morphology, pH of the stomach and antioxidant status of pigs weaned at 28 d were better than pigs weaned at 21 d. These factors supported better growth performance and decreased diarrhea incidence.

Effect of body condition and melatonin implants, inserted at different times of the year, on ovarian activity in goats maintained without male contact from the time of implantation

The aim of the present work was to asses (1) whether body condition (BC) and (2) melatonin implants, inserted at different times of the year between the winter and summer solstices, have an effect on seasonal ovulatory activity in goats without presence of males. Sixty-six Blanca Andaluza does were divided into six groups. Five of these received a melatonin implant on either 18 December (n = 10), 3 February (n = 12), 19 March (n = 12), 30 April (n = 11) or 11 June (n = 11). Following this procedure, the does were completely isolated from bucks. Another 10 goats (YEAR group) were used to monitor natural annual ovarian activity; these females were completely isolated from males over the entire experimental period (from 18 December of one year until 17 December of the next year). Half the does of each group had a low body condition score (BC; ≤2.50; 2.46 ± 0.02), and half had a high BC (≥3.00; 3.24 ± 0.04). Ovulatory activity was monitored via the progesterone concentrations determined in blood samples collected twice per week for 4 months following melatonin implantation, and over 12 months for the YEAR group. Over 46% of the females showed ovarian activity after the melatonin treatment, ranging from the lowest response in December (30%) and the highest one in February (75%) without differences between the dates of melatonin insertion (P &gt; 0.05). However, the response to the melatonin implant was higher in the females with a high BC than in females with a low BC (63% vs 31% for high and of low BC respectively, P &lt; 0.05). The present results indicated that melatonin implants induce ovarian activity in does in the absence of male contact. The moment of melatonin implantation did not modify ovulatory activity. However, the ovulatory response to melatonin implants was higher in the females with a BC of ≥3.00.

Intestinal fat differentially suppresses sham feeding of different gustatory stimuli

To determine the intestinal contribution to short-term satiety for solutions of varying palatability, 10 ml of either 0.15 M NaCl or lipid (Intralipid: 0.125, 0.25, 0.5, and 1.0 kcal/ml) was infused at a rate of 0.5 ml/min into the duodenum of rats that were sham feeding either a liquid diet (0.5 kcal/ml), 0.3 M sucrose (0.4 kcal/ml), or a 0.1 M solution of glucose polymers (Polycose 0.4 kcal/ml). Differences in palatability were estimated by the total consumption of each solution over 90 min in a one-bottle test. The intake of solutions maximally ingested during the saline infusions (Polycose > Sucrose > liquid diet) was the most sensitive to the lipid infusions. All four lipid concentrations suppressed intake of Polycose, the solution consumed the most; the three highest concentrations suppressed intake of sucrose (intermediate consumption), and only the two highest concentrations suppressed intake of the complete diet, the solution consumed the least. Nevertheless, the duration of suppression was shorter for the solutions the rats drank the most. For the solution the rats drank the least (liquid diet), the two high concentrations of lipid that suppressed intake did so for the entire experimental period, whereas for Polycose, al lipid infusions suppressed intake, but it recovered to control levels for all but the highest concentration. Other studies have reported that increasing diet palatability shortens the duration of satiety. The current results suggest that this effect may reflect the duration of intake suppression elicited by nutrients in the intestine.

LOCOMOTOR PERFORMANCE OF CHUM SALMON FRY (ONCORHYNCHUS KETA) DURING OSMOREGULATORY ADAPTATION TO SEA WATER

Transfer into sea water produced an immediate and marked depression of the cruising speed of chum salmon fry. Despite considerable recovery from this initial effect the fish exhibited a continuing slight depression of cruising speed over the entire experimental period (80 hours). Variations in total body levels of chloride and water were significantly correlated with changes in cruising speed, suggesting that variations in activity might be related to the process of osmoregulatory adaptation to sea water. Possible mechanisms underlying this effect have been discussed.