Effects of alginate and resistant starch on feeding patterns,behaviour and performance in ad libitum-fed growing pigs

This study assessed the long-term effects of feeding diets containing either a gelling fibre (alginate (ALG)), or a fermentable fibre (resistant starch (RS)), or both, on feeding patterns, behaviour and growth performance of growing pigs fed ad libitum for 12 weeks. The experiment was set up as a 2×2 factorial arrangement: inclusion of ALG (yes or no) and inclusion of RS (yes or no) in the control diet, resulting in four dietary treatments, that is, ALG−RS− (control), ALG+RS−, ALG−RS+, and ALG+RS+. Both ALG and RS were exchanged for pregelatinized potato starch. A total of 240 pigs in 40 pens were used. From all visits to an electronic feeding station, feed intake and detailed feeding patterns were calculated. Apparent total tract digestibility of energy, dry matter (DM), and CP was determined in week 6. Pigs’ postures and behaviours were scored from live observations in weeks 7 and 12. Dietary treatments did not affect final BW and average daily gain (ADG). ALG reduced energy and DM digestibility (P<0.01). Moreover, ALG increased average daily DM intake, and reduced backfat thickness and carcass gain : digestible energy (DE) intake (P<0.05). RS increased feed intake per meal, meal duration (P<0.05) and inter-meal intervals (P=0.05), and reduced the number of meals per day (P<0.01), but did not affect daily DM intake. Moreover, RS reduced energy, DM and CP digestibility (P<0.01). Average daily DE intake was reduced (P<0.05), and gain : DE intake tended to be increased (P=0.07), whereas carcass gain : DE intake was not affected by RS. In week 12, ALG+RS− increased standing and walking, aggressive, feeder-directed, and drinking behaviours compared with ALG+RS+ (ALG×RS interaction, P<0.05), with ALG−RS− and ALG−RS+ in between. No other ALG×RS interactions were found. In conclusion, pigs fed ALG compensated for the reduced dietary DE content by increasing their feed intake, achieving similar DE intake and ADG as control pigs. Backfat thickness and carcass efficiency were reduced in pigs fed ALG, which also showed increased physical activity. Pigs fed RS changed feeding patterns, but did not increase their feed intake. Despite a lower DE intake, pigs fed RS achieved similar ADG as control pigs by increasing efficiency in DE use. This indicates that the energy utilization of RS in pigs with ad libitum access to feed is close to that of enzymatically digestible starch.     

Twilight activity patterns and angling vulnerability of yellowmouth barracuda (Sphyraena viridensis Cuvier, 1829), a range-expanding thermophilic fish

Among the thermophilic fishes that have become established in the north-western Mediterranean as a consequence of sea warming, the yellowmouth barracuda (Sphyraena viridensis Cuvier, 1829) appears to be one of the most successful and abundant in the coastal rocky environment, having increasingly become the object of recreational and commercial exploitation in the study area. Lure-fishing sessions were carried out from May 2016 to November 2018 in the Catalan Sea (NE Spain) at dawn and dusk, with the aim of providing new insight into the behavioural, spatial and feeding ecology and vulnerability to angling of this poorly known species. Generalized mixed-effects linear models showed that S. viridensis is a crepuscular inshore dweller, whose vulnerability to angling is significantly influenced by solar and lunar light intensities, being highest in the pre-spawn and spawning periods. Asymmetries between dawn and dusk activity patterns were detected, evidently related to a drop in aggressiveness at dusk following the spawning period. The simple study design adopted may be applied to other contexts, aiming to the recognition of several levels of fish vulnerability to angling.     

Behavioral laterality in captive bonobos (Pan paniscus): Replication and extension

We report observational data on behavioral laterality in 10 captive bonobos (Pan paniscus)at the San Diego Zoo. The unimanual measures include carrying, leading limb in locomotion, self-touching, face-touching, reaching, and gestures. We also recorded bimanual feeding in these subjects. A significant population level left-hand bias exists for carrying. Right-hand biases occur for leading limb in locomotion and gestures. During bimanual feeding, the bonobos hold food items with the left hand while feeding with the right hand. Overall, bonobos exhibit behavioral asymmetries that are similar to previous findings in other pongid ape species. The asymmetries in gestures and bimanual feeding represent novel findings with theoretical implications for the origins of tool use and language.     

Infection of the gonads of Glaucosoma hebvaicum by the nematode Philometva lateolabracis: occurrence and host response

The prevalence of infection of the West Australian dhufish Glaucosoma hebraicum off the lower west coast of Australia by Philometra lateolabracis was greater among females than males, which contrasts with the situation with Pagrus auratus in waters off New Zealand. Live P. lateolabracis were represented solely by females and were found only in the gonads of fish of mature size ( L ₅₀ at first maturity = c . 300 mm) caught between December and April and thus during the spawning period of dhufish. Since the gonads were largest during that period, they, and particularly ovaries, would provide an abundant food source in the form of blood. The prevalence of the parasite (live + dead individuals) increased with host body size to reach a maximum of c . 80% in the 700–799 mm length class of females and c . 50% in the largest length class of males. During the spawning period of G hebraicum, P. lateolabracis developed from small, non-gravid females to large gravid females, representing an increase in mass of more than 200 times. The maximum length of P. lateolabracis (470 mm) in G hebraicum is the greatest yet recorded for this species. Gonadosomatic indices provided no evidence that infection by P. lateolabracis leads to a conspicuous atrophy of the ovaries, which contrasts with the situation with the gonads of some of the teleosts infected by Philometra species, and presumably reflects, in part, the small volume of the ovary occupied by P. lateolabracis (c . 3%) and the low intensity of infection (mean = 2.0, maximum = 7). Although the presence of live P. lateolabracis did not stimulate an obvious tissue response by the ovaries during the spawning period of G. hebraicum , both the dead and any live parasites that remain after spawning become encapsulated in fibrous tissue.     

Daily activity of the pest slug Arion lusitanicus under laboratory conditions

The daily activity of the slug Arion lusitanicus was studied using time‐lapse video analysis in the laboratory. Under constant temperature (18°C) and 16–h photoperiod, the activity of slugs was measured in half‐hourly periods as locomotor activity, feeding or resting. Track lengths were determined using image analysis. Locomotion of A. lusitanicus was greatest at 5:30, 1.5 h after sunrise, and at 20:30, 1 h after sunset; least locomotor activity occurred between 13:00 and 14:00. The mean distance travelled by A. lusitanicus in 24 h was 10.8 m. The largest slug was the most active and the smallest the least. Slugs spent 68% of 24 hours resting, mainly under artificial shelter traps, 27% in locomotion and 4% feeding. Feeding occurred mainly during the hours of dakness (76%). All categories of behaviour investigated varied greatly between individuals and also between times of day. Homing to artificial shelters and other roost sites was regularly observed within 24 h (41%), but decreased considerably thereafter. The behavioural patterns proved to be in agreement with those found in a previous field investigation and are therefore also discussed with a view to their importance in pest control.     

Do pollen beetles need pollen? The effect of pollen on oviposition,survival, and development of a flower‐feeding herbivore

Abstract.  1. Pollen is considered to be an important dietary component for many species of flower-feeding herbivores. Its influence on oviposition site selection by the pollen beetle Meligethes aeneus , and on the development of its larvae was investigated.
2. The effects of pollen presence and absence on adult, egg, and larval incidence in the field, and on larval development in the laboratory were compared through the use of Synergy, a composite hybrid oilseed rape Brassica napus variety comprising male-fertile (with pollen) and male-sterile (without pollen) plants.
3. In the field, adult females were more abundant on male-fertile plants during flowering, and a greater proportion of male-fertile than male-sterile buds were accepted for oviposition. These data indicate a possible role of pollen in oviposition site selection by female pollen beetles.
4. The numbers of first instar larvae on the two plant lines did not differ; however, more second instars were found on male-fertile than on male-sterile flowers. This suggests a greater larval survival on male-fertile plants, possibly due to the more readily available food resources and better nutrition afforded by the presence of pollen.
5. Laboratory experiments confirmed that a diet which included pollen improved survival to adulthood and resulted in heavier pupae and adults; however, pollen was not obligatory for larval survival and development.
6. The pollen beetle, previously thought to be an obligate pollen feeder, is therefore more generalist in its requirements for development. These findings may relate to the nutritional and behavioural ecology of other flower-feeding herbivores.     

Host selection by winged colonisers within the Myzus persicae group: a contribution towards understanding host specialisation

Abstract.  1.  Myzus persicae sensu lato demonstrates considerable genetic variation in respect to adaptation to host plants. The subspecies M. persicae nicotianae shows a preference for tobacco, while M. persicae sensu stricto ( s. str. ) for other herbaceous plants. Given that winged colonisers of several aphid species play an important role in selecting host plants, here their role in the host specialisation observed in M. persicae was examined in choice and no-choice tests conducted outdoors, in performance studies, and in DC Electrical Penetration Graph (DC-EPG) studies.
2. In outdoor choice tests, 77% of spring migrants of M. persicae nicotianae chose tobacco, whereas equal proportions of M. persicae s. str. selected tobacco and pepper. In no-choice tests, spring migrants settled more quickly after alighting on host rather than on non host plants, and significantly more alate M. persicae s. str. (27%) than M. persicae nicotianae (2%) left tobacco after walking briefly on the leaf surface, whilst no significant differences were found on pepper. Cross-host transfers significantly reduced the fecundity of both summer and spring migrants of the two subspecies. Finally, the results of no-choice tests and DC-EPG studies showed that winged aphids distinguished their host through cues located on the plant surface or in subcutaneous tissues perceived prior to the initiation of feeding.
3. This study demonstrates the important role of winged colonisers in the evolution of host specialisation in M. persicae . The multifarious divergent selection that the two host forms experience, i.e. the selection against cross-migrants and their subsequent generations, is a crucial factor involved in the development and maintenance of host specialisation and promotes the parallel evolution of improved host-recognition ability.     

ULTRASTRUCTURE AND ECOLOGY OF AUREOCOCCUS ANOPHAGEFERENS GEN. ET SP. NOV. (CHRYSOPHYCEAE): THE DOMINANT PICOPLANKTER DURING A BLOOM IN NARRAGANSETT BAY,RHODE ISLAND,SUMMER 19851

Observations of a marked cessation of feeding in filter feeding animals maintained in flowing Narragansett Bay seawater in June 1985 drew our attention to a bloom of a golden alga 2 μm in diameter at unprecedented populations of 10⁹ cells. L^?1. This picoplankter lacked morphological features useful in discriminating it from other similar sized forms with either phase contrast or epifluorescence light microscopy. Natural populations of picoplankton, obtained from the height of the bloom until its decline, were examined in thin section with transmission electron microscopy. A cell with a single chloroplast, nucleus, and mitochondrion and an unusual exocellular polysaccharide-like layer was apparently the bloom alga. The ultrastructure of this alga is consistent with that of the Chrysophyceae, and a new genus and species, Aureococcus anophagefferens is described. Attempts to grow this previously unrecognized picoplanktonic alga as an obligate phototroph failed and only yielded cultures of other previously described picoalgae. Facultative and obligate phagotrophic protists with ingested cells of Aureococcus were only observed as the bloom waned and minute diatoms became common. Cells of A. anophagefferens with virus particles typical for picoalgae occurred throughout the bloom. Populations of the usually dominant photosynthetic picoplankter, the cyanobacterium Synechococcus Nägeli, were depressed during the bloom. This could be due in part to selective grazing on Synechococcus rather than Aureococcus by elevated populations of Calycomonas ovalis Wulff which accompanied the algal bloom.     

Amphibious behaviour and feeding ecology of the four-eyed blenny (Dialommus fuscus, Labrisomidae) in the intertidal zone of the island of Santa Cruz (Galapagos, Ecuador)

The labrisomid Dialommus fuscus , endemic to the Galapagos archipelago, is a predator of crustaceans, which moves up and down the intertidal zone with the tides. Its divided eye and elongated body permit it to forage in the wet sections of the intertidal habitat during low tide, both on the rocks and below the water line and in tide pools. Compared with other intertidal fishes (e.g. Bathygobius sp.), it was present on the rock flat in significantly smaller tide pools nearer to the water line during low tide.