Amount Of Time Feeding Research Articles

PSII-20 Feeding behavior of pigs fed dietary amino acid levels adjusted according to the circadian rhythm

Abstract Pigs are diurnal animals that present feed intake during daylight hours, with feeding peaks in the early morning and late afternoon. However, it is possible that the concentration of amino acids (AA) in the diet throughout the day changes the meal pattern of the pigs. Therefore, the objective of this study was to evaluate the feeding behavior of growing-finishing pigs subjected to adjustment of the concentration of AA in the diet according to the circadian rhythm. Sixty-eight (body weight = 25 kg ± 2.67) barrows were assigned to four treatments, being a daily feeding program (DP) and three sequential feeding programs (SEQ). In DP, dietary AA concentration was adjusted daily, providing 100% of the standardized ileal digestibility (SID) recommendation for the 24-h period. In SEQ, the daily dietary AA concentration was adjusted every 12 h, providing a low AA concentration from 0000 to 1159 h and a high AA concentration from 1200 to 2359 h. The low and high AA concentrations of the SEQ corresponded to ±20%, ±30% and ±40% of daily AA requirements. The experiment lasted 82 d and was divided into three phases. Meal pattern variables were recorded in real time by precision feeders. The information obtained was grouped into four periods: PE1, from 0000-0600 h; PE2, 0601-12:00 h; PE3, 1201-1800 h; and PE4, 1801-2359 h. From this database, the visits to the feeder (n), meals (n), amount of time feeding (min), feed intake (g), and feed intake rate (g/min) were calculated for each period, within each experimental phase. The analysis of variance was performed considering the effects of feeding programs (FP), periods (PE), and their interaction (FP×PE), considered significant when P < 0.05. There was no interaction between FP and PE (P > 0.05; Table1). The visits to the feeder were greater (P < 0.01) in PE2 and PE3 compared with PE1 in phase one and compared with PE1 and PE4 in phases two and three. The meals, amount of time feeding, and feed intake was greater (P < 0.01) in PE2 and PE3 in all phases. Regarding feed intake rate, an PE effect (P ≤ 0.01) was observed in all phases and there was an effect of FP (P < 0.01) in phases one and three. In phase one, pigs ingested feed faster in PE3 than PE1, and in phase three feed intake rate in PE1 was less than in the other (P < 0.01). During phase one, SEQ40 feed intake rate was lower than SEQ30, while in phase three SEQ40 showed lower feed intake rate compared with SEQ30 and DP. Pigs showed greater feeding activity from 0600 to 1800 h. The AA concentration in the diet adjusted according to the circadian rhythm did not change the meal pattern of the pigs throughout the day. However, a decreased feed intake rate was observed in SEQ40 group in phases one and three.

Development of a feeding strategy for Haliotis discus hannai ♀ × Haliotis fulgens ♂ hybrids and parental H. discus hannai

The hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂ (DF) shows obvious growth advantages compared with one of its parents, H. discus hannai (DD); however, the reasons for these advantages are not fully understood. Using a video surveillance system, the current study showed that the feeding behaviors of DD and DF exhibited an obvious circadian rhythm, with significantly more feeding at night by DD and DF than during the day. In addition, the amount of time feeding by DF during the day and at night was significantly higher compared with that of DD, especially at ZT8 (20:00), ZT12 (24:00), ZT16 (04:00), and ZT20 (08:00), with the proportion of time feeding by DF increasing 2.22-, 1.60-, 2.71-, and 2.40-fold compared with those of DD, respectively. The maximum values of pepsase activity in DD and DF, of α-amylase activity in DD, and of alginate lyase activity in DF coincided with the peak feeding period. Relative to the changes in expression levels of neuropeptide Y receptor (NPYR) in the intestine, diurnal changes in NPYR expression levels in cerebral ganglia were consistent with the changes in feeding behavior, being highest at 24:00 h in both DD and DF and then declining. There was no significant difference in the circadian expression levels of cholecystokinin receptor (CCKR) in the cerebral ganglia, whereas, in the intestinal tract, peak CCKR expression levels coincided with its anorexigenic effect; the expression levels of CCKR in the intestinal tract exhibited a significant circadian rhythm in DD. These results explain the growth advantage of DF over DD in terms of feeding behavior and digestive physiology, and support the hypothesis that diurnal changes in feeding-related genes in the nervous and digestive systems are correlated with the initiation of abalone feeding behavior. Our findings also provide guidance for developing a suitable feeding strategy for, and improving the efficiency of, the production of abalone.

Precision feeding strategy for growing pigs under heat stress conditions.

This study evaluated the responses of individual daily precision (IPF) and conventional 2-phase (CON) feeding systems (FS) in terms of pig growth performance, nutrient balance, serum parameters, and meal patterns of growing pigs reared under thermoneutral (TN: 23 °C) and heat stress (high temperature [HT]: 30 °C) conditions. The animals in each treatment were assigned on the basis of equal BW to the experimental treatments (12 animals per treatment at 41.0 ± 4.87 kg of BW). The experiment lasted 55 d (phase 1 from days 0 to 27 and phase 2 from days 28 to 55). Pigs fed CON received within each phase a constant blend of diets with high and low nutrient density supplying the estimated nutrient requirements of the group, whereas the IPF pigs received daily a personalized blend providing the estimated amount of nutrients according to individual feed intake and body weight information. Body mineral content, and lean and fat masses were assessed through dual-energy X-ray absorptiometry at the beginning and end of each phase. Data were analyzed using a linear mixed-effect model, with fixed effects of the FS, temperature (AT), and the 2-way interaction between FS and AT and random effects of blocks. In relation to CON pigs, IPF pigs reduced (P < 0.05) Lys (19%), protein (16%), and P (14%) intake without impairing (P > 0.05) body composition. Nitrogen excretion was 24% lower (P < 0.05) in IPF pigs than in CON pigs; however, both groups had similar N retention efficiency thoroughly the trial. Amount of time feeding, feed intake rate, and feed intake per meal were 15% lower (P < 0.05) in pigs raised under HT than under TN conditions. During the phase 2, only amount of time feeding, feed intake rate, and feed intake per meal were decreased (P < 0.05) in pigs under HT conditions during nocturnal (2000 to 0500 h) and diurnal (0501 to 1959 h) periods. Haptoglobin levels were affected by the AT, showing an increase of 70% and 43% in HT at 28 and 55 d of the experiment, respectively. Pigs raised under HT conditions had 10% lower (P < 0.05) serum albumin concentration at day 55 than those under TN conditions. For serum urea concentrations, IPF pigs had 28% lower (P < 0.01) levels than CON pigs. Even though HT conditions considerably reduced growth performance and activated inflammatory responses in growing pigs, IPF was not able to rescue performance during HT; however, it was equally effective at improving nutrient utilization and maintaining body composition in HT and TN conditions.

The effect of feeding system at weaning on performance, health and feeding behaviour of pigs of different sizes

Pigs weaned at 31 to 34 days of age (n=280) were mixed into groups of 10 and fed from either feeders (2 feeding places per pen) or troughs (10 feeding places per pen). Analyses on performance, diarrhoea scores and feeding behaviour were made separately on small-, medium- and large-sized pigs, defined as their relative size in the group. During the second week after weaning, feed conversion ratio (FCR) was lower for pigs fed from feeders. Trough feeding resulted in lower total diarrhoea scores for small (p=0.002) and large (p=0.04), and higher scores for medium pigs (p=0.03). Small pigs had lower scores on individual days around the peak on day 6. All three size categories of pigs spent a numerically higher amount of time feeding when fed from a trough. Feeding bouts were longer in pigs fed from a trough (p=0.0002 – 0.05).

Antipredator vigilance in birds: Modelling the ‘edge’ effect

Many animals spend a large proportion of their time either foraging for food or watching out for predators (antipredator vigilance). There have been many theoretical and empirical studies investigating the trade-off between these two activities, especially in birds. Previous models of antipredator vigilance assume that all birds within the group spend the same amount of time feeding. However, many empirical studies have shown that individuals on the edge of flocks are more vigilant. Here we describe a vigilance model which investigates the effect of position on the birds’ strategies by dividing the feeding area into an inner and outer region. The model examines how various parameters such as food availability and predation risk affect the strategies of individual birds according to whether they are in the inner or outer region. Our model predicts that birds in the outer group are always more vigilant than those in the inner region. Birds in the centre receive a higher payoff in each of the wide range of scenarios that we have considered, and so our model also indicates why dominant birds would choose to feed in the centre of the group; a prediction in accord with several empirical studies.

BEHAVIOR OF WEB-INVADING SPIDERS ARGYRODES ARGENTATUS (THERIDIIDAE) IN ARGIOPE APPENSA (ARANEIDAE) HOST WEBS IN GUAM

Most Argyrodes live in the webs of other spiders, stealing food from the host, scavenging small prey from the web or killing and eating the host. I observed the behavior of A. argentatus from Guam, where it is a frequent inhabitant of the large orb webs of Argiope appensa. I examined the pro- portion of time spent in different activities, whether behavior differed between the sexes and if population density of Argyrodes on a host web affects Argyrodes behavior. Argyrodes spent 55% of the time hanging immobile and inverted in the support strands at the webs' margin. This was significantly more time than that spent in stationary activity, forward movement at the web's margin, feeding, foraging on the sticky spiral or in aggressive interaction. Females foraged significantly more often than did males, though the sexes spent about the same amount of time feeding and in other activities. Females also engaged in more bouts of feeding and 21% of these bouts were at prey bundles prepared by the host. In contrast, males invariably foraged for small insects unnoticed by the host.

The behavioural priorities of laying hens: the effects of two methods of environment enrichment on time budgets

In the first experiment, a comparison was made of the time budgets of laying hens ( Gallus gallus domesticus) in an enriched condition, in which various objects were added to their pen, and an unenriched condition, the same pen but without these objects. Assuming a fixed time budget, greater choices in the enriched condition would increase some behaviours at the expense of others, providing a relative measure of importance. In a second experiment, one group had woodchips on the floor with food and the other had woodchips on the floor without food (available from a hopper). In the first experiment, frequency of dust-bathing decreased in the enriched condition. Hens in the unenriched condition spent more time preening, drinking, social pecking at others and being aggressive which also increased in the second experiment in the hopper food condition. In both experiments, there was no difference in the amount of time feeding and also pecking and scratching even though food was not available in the litter in the unenriched condition. The results of the second experiment show that feeding on the floor alone, i.e., not in combination with environmental enrichment, also reduces aggression, whereas it has no influence on social pecking.

Feeding behaviour of adult tiger prawns, Penaeus esculentus, under laboratory conditions

Adult tiger prawns, P. esculentus, when offered a choice of food, showed significant preferences. They preferred feeding on tissue from the prawn Metapenaeus bennettae to tissue from the bivalve Perna canaliculus but preferred P. canaliculus to the prawn Penaeus longistylus. When given a choice of two bivalves, they preferred Donax deltoides to Perna canaliculus. Prawns preferred fresh food to food that had been soaked for several hours. If food was given only at dusk, feeding occurred mainly in the first half of the night. If additional fresh food was given at midnight, then an equal amount of feeding occurred after midnight. The prawns spent short periods (mean 9.3 min) at the food. These were separated by non-feeding intervals with a mean length of 42 min. This behaviour was repeated about six times each night. Tiger prawns filled their foreguts to about 60% of capacity within 10 min of beginning feeding and could clear about 50% of the content in 30 min and nearly 55% in 60 min. Females and males spent the same amount of time feeding. When starved, P. esculentus emerged from the substrate for longer periods at night, moved around more, and emerged during the day.

Cost of prey capture, growth rate and ration size in pike, Esox lucius L., as functions of prey weight

Prey intake, amount of time feeding, pursuit and manipulation times and growth rate were studied in the pike, Esox lucius, in relation to prey weight. Predator and prey were observed in tanks at 15°C and with a 14:10 h LD photoperiod. A total of 444 captures were recorded from five 1 g prey weight groups varying from 0 to 4.9 g. Ten pike were used weighing between 50 and 149 g.As prey weight increased, the number and weight of prey consumed decreased as did the time spent feeding, which became concentrated into the first trial of the day. Pursuit time did not vary with prey weight, but manipulation time and the weight of prey gained per unit pursuit plus manipulation time increased with prey weight.The growth rate of pike was a positive function of ration size and a negative function of the amount of time spent capturing each gramme of prey (capture cost). Growth rate was also correlated with the mean length and weight of prey eaten.The most profitable prey, as estimated from optimal foraging theory, need only be available once every 84 min for pike to maximize their net energy gain. The data show that feeding behaviour can have a direct influence on the reproductive success of pike through its effect on growth rate.