Daily feeding rhythm linked to microbiome composition in two zooplankton species

Host-associated microbial communities are impacted by external and within-host factors, i.e., diet and feeding behavior. For organisms known to have a circadian rhythm in feeding behavior, microbiome composition is likely impacted by the different rates of microbe introduction and removal across a daily cycle, in addition to any diet-induced changes in microbial interactions. Here, we measured feeding behavior and used 16S rRNA sequencing to compare the microbial community across a diel cycle in two distantly related species of Daphnia, that differ in their life history traits, to assess how daily feeding patterns impact microbiome composition. We find that Daphnia species reared under similar laboratory conditions have significantly different microbial communities. Additionally, we reveal that Daphnia have daily differences in their microbial composition that correspond with feeding behavior, such that there is greater microbiome diversity at night during the host's active feeding phase. These results highlight that zooplankton microbiomes are relatively distinct and are likely influenced by host phylogeny.

The Food-entrainable Oscillator Is a Complex of Non-SCN Activity Bout Oscillators Uncoupled From the SCN Circadian Pacemaker

The food-entrainable oscillator, which underlies the prefeeding activity peak developed by restricted daily feeding (RF) in rodents, does not depend on the circadian pacemaker in the suprachiasmatic nucleus (SCN) or on the known clock genes. In the present study, to clarify the roles of SCN circadian pacemaker and nutrient conditions on the development of prefeeding activity peak, RF of 3-h daily feeding was imposed on four groups of adult male mice for 10 cycles at different circadian times, zeitgeber time (ZT)2, ZT8, ZT14, and ZT20, where ZT0 is the time of lights-on in LD12:12. Seven days after the termination of RF session with ad libitum feeding in between, total food deprivation (FD) for 72 h was imposed. Wheel-running activity and core body temperature were measured throughout the experiment. Immediately after the RF or FD session, the PER2::LUC rhythms were measured in the cultured SCN slices and peripheral tissues. Not only the buildup process and magnitude of the prefeeding activity peak, but also the percentages of nocturnal activity and hypothermia developed under RF were significantly different among the four groups, indicating the involvement of light entrained circadian pacemaker. The buildup of prefeeding activity peak was accomplished by either phase-advance or phase-delay shifts (or both) of activity bouts comprising a nocturnal band. Hypothermia under FD was less prominent in RF-exposed mice than in naïve counterparts, indicating that restricted feeding increases tolerance to caloric restriction as well as to the heat loss mechanism. RF phase-shifted the peripheral clocks but FD did not affect the clocks in any tissue examined. These findings are better understood by assuming multiple bout oscillators, which are located outside the SCN and directly drive activity bouts uncoupled from the circadian pacemaker by RF or hypothermia.

524 Late-Breaking: Growth Performance of Neonatal Calves Fed Milk Replacer 2 versus 3 Times per Day

Several calf studies demonstrate advantages when feeding greater protein and/or milk solids amounts, however studies comparing 2x/d versus 3x/d feeding are limited. Forty 2- to 5-d old Holstein bull calves were blocked by body weight (BW) and randomly assigned to 1 of 2 treatments. Treatments were: 1) 2X: milk replacer (MR) fed 2x/d; and 2) 3X: MR fed 3x/d. The MR was fed at 15% solids at 0630 and 1800 h and the 3rd 3X feeding was at 1200 h. 2X calves were fed MR at 0.567 kg/d for d 1–14, increased to 0.85 kg/d for d 15–35, and reduced to 1x/d at 0.425 kg/d for d 36–42 for the 42 d study. 3X calves were fed MR 0.851 kg/d for d 1–14, increased to 1.275 kg/d for d 15–35, and reduced to 1x/d at 0.425 kg/d for d 36–42. Calf starter (CS) and water were free choice. Initial BW was a significant (P < 0.01) covariate and BW (55.6 and 57.3 kg for 2X and 3X, respectively) tended (P < 0.09) to be greater for calves fed 3X compared with 2X fed calves, but BW gains (25.5 and 27.7 kg) were similar (P > 0.10). A treatment by week interaction (P < 0.01) demonstrated variable BW gains. Intake of CS (0.28 and 0.13 kg/d) was approximately 63% lower (P < 0.04) for calves fed 3X compared with calves fed 2X. Feed conversions (0.65 and 0.60 kg/kg) were greater (P < 0.04) for calves fed 2X compared with calves fed 3X. Calves fed 2X had less scours (fecal score=0; 34.3 and 29.7 d) compared with 3X fed calves. Providing an additional MR feeding demonstrated minimal BW gains. Providing a 3rd daily feeding greatly reduces CS intake and inhibits the transition needed for weaning calves.

Video surveillance methods to evaluate individual feeding response in rainbow trout (Oncorhynchus mykiss, Walbaum)—implications for feeding regime optimisation

Precisely analysing and optimising feeding regimes is central to salmonid growth performance and delivery of special diets. The current study developed novel video surveillance methods and analysis techniques to assess individual feed intake and minimum pellet intake (MPI) in individually identified juvenile rainbow trout, Oncorhynchus mykiss. Three trials were conducted to test the impact of short-term starvation (N=112 [16 tanks, 7 fish per tank], average weight=27.1±3.4g, age= 119 days), portion numbers per feeding (N=105 [15 tanks, 7 fish per tank], average weight=22.8±2.1g, age= 99 days) and varied numbers of daily feeding events (N=84 [12 tanks, 7 fish per tank], average weight=32.4±3.3g, age= 133 days). All trails were carried out in a recirculating aquaculture system with 20 tanks held at 15 ± 0.5°C. All individuals were code-tagged and high quality video images were taken and analysed to identify all feeding interactions. Individual trout feeding activity under different feeding regimes could be precisely analysed with the video methods developed. Moving from one to two daily feeding events doubled pellet intake per fish from 27.4 ± 5.8 to 52.8 ± 11.5 pellets. Pellet intake (58.8 ± 24.2 pellets) did not increase at three daily feeding events but became more variable across fish. MPI nearly doubled to 30 pellets in fish receiving two daily feeding events (MPI30: chi-squared = 8.74, df = 2, p = 0.01). Short-term starvation had no influence on intake (28 ± 8 pellets/fish) or MPI. Increasing portion number from one (27.8 ± 7.4 pellets fish−1) to two (31.1 ± 7.4 pellets fish−1) or more did not significantly increase the number of ingested pellets. Adjusting the feeding regime by increasing daily feeding events to two, possibly combined with multiple portions, can increase pellet intake and reduce the heteroscedasticity of pellet intake. The methods presented in this study are viable for analysing feeding regimes for juvenile rainbow trout and controlled feedstock/supplement delivery. Implications for analyses with other species and for vaccination optimisation are discussed.

EFEK PEMUASAAN DAN PAKAN FERMENTASI TERHADAP LAJU PERTUMBUHAN DAN FEED CONVERTION RATIO IKAN NILA (Oreochromis niloticus)

The main fish farming activities at the enlargement stage require a feed cost of around 60% of the total production cost. Efforts that can be made to reduce the cost of feed are through the starvation and fermentation of feed. This study uses a Completely Randomized Design (CRD) which is 3 treatments and 3 replications. The treatments tried were treatment A = protein feed 31-33% without fermentation (daily feeding), treatment B = protein feed 21-23% fermentation,, (daily feeding), treatment C = protein feed 21-23% fermentation, (1 day starvation 1 day re-feeding), treatment D = protein feed 21-23% fermentation, (1 day starvation 2 days re-feeding), E treatment = protein feed 21-23% fermentation, n (1 day starvation 3 days re-feeding). The study was conducted in a walled pond which was sealed using a net (50 x 50 x 100 cm3), feeding 3 times a day. The results showed that the treatment E effectively suppressed the FCR value and offset the daily growth rate of Treatment A. In addition, treatment E has the same FCR value as treatments B, C, D but treatment E has a higher daily growth rate.Keywords: starvation, fermentation, growth, FCR

Social Network Analysis of Agonistic Behaviour and Its Association with Economically Important Traits in Pigs

Aggression behaviour has several negative consequences on the performance and welfare of pigs. Here, the Social Network Analysis (SNA) approach was employed to (1) identify individual traits that describe the role of each animal in the aggression; (2) investigate the association of these traits with performance and feeding behaviour traits. The study was conducted on 326 Duroc pigs reared in 29 pens. Several individual centrality traits were identified and used to calculate the Social Rank Index. The Dominant, Subordinate, and Isolated animals represented 21.1%, 57.5% and 21.4%, respectively. No significant correlations were observed between out-degree (number of initiated agonistic behaviours) and growth traits, indicating the similarity of growth patterns for dominant and non-dominant animals. Furthermore, out-degree was correlated positively with average daily occupation time (time at the feeder/day) and average daily feeding frequency (number of visits to the feeder/day) but negatively with average daily feeding rate (gr/min). This may indicate the ability of non-dominant pigs to modify their behaviour to obtain their requirements. The Hamming distances between networks showed that there is no common behaviour pattern between pens. In conclusion, SNA showed the potential for extracting behaviour traits that could be used to improve pig performance and welfare.

Organoid Maturation by Circadian Entrainment

Stem cell-derived tissues that recap endogenous physiology are key for regenerative medicine. Yet, most methods yield products that function like fetal, not adult tissues. Organoids are typically grown in constant environments, while our tissues mature along with behavioral cycles. Here, we show that inducing circadian rhythms in pancreatic islet organoids, by entraining them to daily feeding-fasting cycles, elicits their metabolic maturation. Our results show that rhythms can be harnessed to further functional maturation of organoids destined for human therapeutics.

Examination of high-resolution feed intake data of grower finisher pigs confronted with typical short-term disturbances in stable routine

Modern pig feeding systems allow the collection of highly detailed feeding data for each animal. These data enable the examination of individual feeding behaviours to assess an animal’s wellbeing. As such, four different treatments ‒ undisturbed control, starving (no feed for 24 h, restrictive feeding), feed change (changes in feed composition) and social stress (exchanging of animals between the pens and short-term reduction of accessible water) ‒ were designed to simulate typical short-term disturbances in a practical stable routine. Each treatment was conducted over 2 pens with 12 animals each. Zootechnical performance and feed intake behaviour measures were assessed for each animal. Treatments did not affect zootechnical performance. Results showed that short-term disturbances did not influence feed intake behaviours, such as daily feed intake, amount of intake per feeder visit, number of daily feeder visits and daily feeding action with highest feed intake. Animals developed individual feeding patterns that persisted through artificial short-term disturbances. However, data suggested that an individual animal’s behavioural pattern was strongly influenced by the group (pen) due to group dynamics among animals.