Porcine digestible peptides as alternative protein source in weaner diets: effects on performance and systemic cytokine profile in pigs followed from weaning to slaughter.

Porcine digestible peptides (PDP) are high-quality hydrolysed proteins obtained from porcine intestinal mucosa as a by-product of the heparin manufacturing process. PDP contain bioactive peptides and are used as alternative protein sources in several animal species, including pigs. We aimed to explore the (carry-over) effects of feeding PDP to weaned piglets on performance and systemic cytokine levels of pigs followed until slaughter. A total of 192 piglets were allocated to one of two dietary treatments: control (CON) or PDP weaner diets. PDP was included at 5.0% until day 13 post-weaning at the expense of skimmed milk powder and partial replacement of soybean meal, and at 2.5% between days 13 and 34 post-weaning at the expense of soy protein concentrate. Grower-finishers were fed commercial diets according to a 3-phase feeding scheme until slaughter, when carcass traits were determined. Six pigs were housed per weaner pen and eight per grower-finisher pen with 16 and 10 pens per treatment, respectively. Pigs were weighed at the start and at the end of each phase, and feed intake was recorded. Faecal consistency was recorded twice a week in the weaner facility. Ten pigs per treatment were sampled for blood at days 13, 34 and 69 post-weaning. We found that PDP-fed piglets had a higher feed intake in the first two weeks post-weaning compared to CON-fed piglets (+32 g/pig per day; P = 0.02). Moreover, piglets in the PDP group showed improved feed conversion between days 13 and 34 versus the CON group (1.36 vs 1.43; P = 0.03). Piglets that were fed with PDP in the weaner diets tended to grow faster in the grower-finisher period (+32 g/pig per day; P = 0.07), tended to reach slaughter age earlier (129.9 vs 131.5 days; P = 0.07) and had a lower dressing percentage at slaughter (76.3 vs 76.7%, P = 0.045) than piglets previously fed with CON. Additionally, PDP-fed piglets showed higher serum levels of pro-inflammatory cytokines interleukin (IL)-12 (P = 0.02), tumour necrosis factor-alpha (P = 0.02), interferon-gamma (P = 0.03) and IL-8 (at day 34 post-weaning, P = 0.06) as well as anti-inflammatory cytokines transforming growth factor-beta (P = 0.02), IL-4 (P = 0.04) and IL-10 (at day 34 post-weaning, P = 0.02). No significant differences among dietary treatments were observed regarding faecal consistency of weaned piglets and carcass weight, lean meat percentage, muscle depth, and back fat thickness at slaughter. We conclude that feeding PDP, as an alternative to conventional milk and soy protein sources, showed positive effects on pig performance, not only during the provisioning period but also thereafter into the grower-finisher phase.

Exploring the association between microbiota and behaviour in suckling piglets.

It is increasingly recognised that the microbes residing in the gastrointestinal tract can influence brain physiology and behaviour, via the microbiota-gut-brain axis. Here, we made a first explorative evaluation at the association between the gut microbiota and behaviour in suckling piglets. 16S microbiota profiling information was obtained from two independent replicate experiments at 2 and 4 weeks of age. Piglets underwent a backtest to assess their personality or coping style at 2 weeks of age, and were subjected to a combined open field and novel object test at 3.5 weeks of age, recording anxiety-related and exploratory behaviour. The number of squeals vocalised during the open field test was associated with microbial groups such as Coprococcus 3 and CAG-873, whereas in the novel object test, explorative behaviour was significantly associated with microbial genera like Atopobium and Prevotella. Overall, this study explores the microbiota-behavioural relation by employing multivariate analysis and exemplifies the importance of individualised analyses when evaluating such relationships.

Early life feeding accelerates gut microbiome maturation and suppresses acute post-weaning stress in piglets.

Early life microbiome perturbations can have important effects on host development, physiology and behaviour. In this longitudinal study, we evaluated the impact of early feeding on gut microbiome colonization in neonatal piglets. Early-fed (EF) piglets had access to a customized fibrous diet from 2 days after birth until weaning in addition to mother's milk, whereas control piglets suckled mother's milk only. Rectal swabs were collected at multiple time points until 6 weeks of age to investigate microbiota development using 16S rRNA gene profiling. The dynamic pre-weaning microbiota colonization was followed by a relatively stable post-weaning microbiota, represented by Prevotella, Roseburia, Faecalibacterium, Ruminococcus, Megasphaera, Catenibacterium and Subdoligranulum. EF piglets showed an accelerated microbiota maturation, characterized by increased microbial diversity, pre-weaning emergence of post-weaning-associated microbes and a more rapid decline of typical pre-weaning microbes. Furthermore, the individual eating behaviour scores of piglets quantitatively correlated with their accelerated microbiome. Importantly, EF piglets displayed a smoother relative weight gain and tended to reach a higher relative weight gain, in addition to reduced diarrhoea scores in the first week post-weaning. Overall, these findings demonstrate the beneficial impact of early feeding on microbiota development as well as pig health and performance during the weaning transition.

Impact of early-life feeding on local intestinal microbiota and digestive system development in piglets.

Early-life gut microbial colonisation is known to influence host physiology and development, shaping its phenotype. The developing gastro-intestinal tract of neonatal piglets provides a "window of opportunity" for programming their intestinal microbiota composition and corresponding intestinal development. Here, we investigated the impact of early feeding on jejunum and colon microbiota composition, and intestinal maturation in suckling piglets. From two days of age, early-fed (EF; n = 6 litters) piglets had access to solid feed containing a mixture of fibres till weaning (day29) in addition to sow's milk, whereas the control (CON; n = 6 litters) piglets exclusively fed on sow's milk. Early feeding elicited a significant impact on the colon microbiota, whereas no such effect was seen in the jejunal and ileal microbiota. Quantified eating behavioural scores could significantly explain the variation in microbiota composition of EF piglets and support their classification into good, moderate, and bad eaters. Members of the Lachnospiraceae family, and the genera Eubacterium, Prevotella, and Ruminococcus were quantitatively associated with eating scores. EF piglets were found to have a decreased pH in caecum and colon, which coincided with increased short-chain fatty acid (SCFA) concentrations. Moreover, they also had increased weights and lengths of several intestinal tract segments, as well as a decreased villus-crypt ratio in jejunal mucosa and an increased abundance of proliferative cells in colon mucosa. The approaches in this study indicate that early feeding of a mixed-fibre (pre-weaning) diet changes the microbiota composition, pH, and fermentation products in the distal gut of piglets, while it also alters both macroscopic and microscopic intestinal measurements. These results exemplify the potential of early feeding to modulate intestinal development in young piglets.

Influence of the metabolic state during lactation on milk production in modern sows.

Selection for prolificacy in sows has resulted in higher metabolic demands during lactation. In addition, modern sows have an increased genetic merit for leanness. Consequently, sow metabolism during lactation has changed, possibly affecting milk production and litter weight gain. The aim of this study was to investigate the effect of lactational feed intake on milk production and relations between mobilization of body tissues (adipose tissue or skeletal muscle) and milk production in modern sows with a different lactational feed intake. A total of 36 primiparous sows were used, which were either full-fed (6.5 kg/day) or restricted-fed (3.25 kg/day) during the last 2 weeks of a 24-day lactation. Restricted-fed sows had a lower milk fat percentage at weaning and a lower litter weight gain and estimated milk fat and protein production in the last week of lactation. Next, several relations between sow body condition (loss) and milk production variables were identified. Sow BW, loin muscle depth and backfat depth at parturition were positively related to milk fat production in the last week of lactation. In addition, milk fat production was related to the backfat depth loss while milk protein production was related to the loin muscle depth loss during lactation. Backfat depth and loin muscle depth at parturition were positively related to lactational backfat depth loss or muscle depth loss, respectively. Together, results suggest that sows which have more available resources during lactation, either from a higher amount of body tissues at parturition or from an increased feed intake during lactation, direct more energy toward milk production to support a higher litter weight gain. In addition, results show that the type of milk nutrients that sows produce (i.e. milk fat or milk protein) is highly related to the type of body tissues that are mobilized during lactation. Interestingly, relations between sow body condition and milk production were all independent of feed level during lactation. Sow management strategies to increase milk production and litter growth in modern sows may focus on improving sow body condition at the start of lactation or increasing feed intake during lactation.

Consequences of negative energy balance on follicular development and oocyte quality in primiparous sows†.

Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can influence the development of follicles and oocytes that will give rise to the next litter. To study effects of a lactational NEB on follicular development, we used 36 primiparous sows of which 18 were subjected to feed restriction (3.25 kg/day) and 18 were full-fed (6.5 kg/day) during the last 2 weeks of a 24.1 ± 0.3 day lactation. Feed restriction resulted in a 70% larger lactational body weight loss and 76% higher longissimus dorsi depth loss, but similar amounts of backfat loss compared to the full fed sows. These changes were accompanied by lower plasma insulin-like growth factor 1 (IGF1) and higher plasma creatinine levels in the restricted sows from the last week of lactation onward. Ovaries were collected 48 h after weaning. Restricted sows had a lower average size of the 15 largest follicles (-26%) and cumulus-oocyte complexes showed less expansion after 22 h in vitro maturation (-26%). Less zygotes of restricted sows reached the metaphase stage 24 h after in vitro fertilization and showed a higher incidence of polyspermy (+89%). This shows that feed restriction had severe consequences on oocyte developmental competence. Follicular fluid of restricted sows had lower IGF1 (-56%) and steroid levels (e.g., ß-estradiol, progestins, and androgens), which indicated that follicles of restricted sows were less competent to produce steroids and growth factors needed for oocytes to obtain full developmental competence.

Legitimate and Reliable Determination of the Age-Related Intestinal Microbiome in Young Piglets; Rectal Swabs and Fecal Samples Provide Comparable Insights.

A prerequisite for reliable microbiota analysis is having an effective and consistent sampling method. Fecal sampling, commonly used to study the intestinal microbiome, might not be suitable in all situations, especially considering the potential difficulties in obtaining fresh feces from young animals. Indeed, this study shows that the success rate of collecting fecal samples from young piglets (<2 weeks of age) was very low. Therefore, we evaluated rectal swabs as an alternative sample type (to feces) for studying porcine microbiome development and performed a comparative analysis of microbiome composition obtained from fresh fecal samples and rectal swabs in 15 healthy piglets at seven (6 piglets) and 20 (9 piglets) days of age. Three samples (fresh feces, rectal swab before and after defecation) were collected from individual piglets and microbiome composition was assessed by 16S rRNA gene sequencing. The results demonstrated that rectal swabs and fecal samples provide similar microbiome composition profiles, with samples clustering predominantly by individual animal rather than sample type. Furthermore, regardless of the sample type, the biological interpretation with respect to microbiota colonization patterns associated with different ages (7 and 20 days) was found to be comparable. Independent of sample type, we observed age-related changes like increasing microbiota diversity and alterations in relative abundances of the phyla Firmicutes, Bacteroidetes, and Fusobacteria, which was also reflected in consistent family- and genus-level microbiota changes. This study establishes that rectal swabs are a suitable alternative sample type to study the porcine microbiome development in early life, when fecal sampling is challenging.

The Quest for Welfare-Friendly Feeding of Broiler Breeders: Effects of Daily vs. 5:2 Feed Restriction Schedules.

Restricted feeding of broiler breeders is required for improved long-term health and welfare. Because feeding frustration and hunger are major welfare concerns during rearing, many suggestions have been made to decrease the negative feelings of hunger while maintaining suitable growth rates and reproductive health. Non-daily ("skip-a-day") feeding schedules are commonly used around the world to increase portion sizes at meal times while restricting intake but these practices are prohibited in many countries due to welfare concerns on fasting days. We compared birds raised on a non-daily feeding schedule (2 non-consecutive fasting days per week, 5:2), previously suggested as a welfare-friendlier non-daily alternative, to birds raised on daily feed restriction. We found signs of increased physiological stress levels in 5:2 birds, including elevated heterophil to lymphocyte ratios (1.00 for 5:2 vs. 0.75 for daily fed at 12 weeks of age), increased adiposity (0.21% lean body weight [LBW] for 5:2 vs. 0.13% LBW for daily fed), and reduced muscle growth (pectoral muscle 5.94% LBW for 5:2 vs. 6.52% LBW for daily fed). At the same time, 5:2 birds showed signs of lower anxiety before feeding times (activity was reduced from 10.30 in daily fed to 4.85) which may be a result of the lower feed competition associated with larger portion sizes. Although we found no difference in latency to first head movement in tonic immobility between the treatments (136.5 s on average for both groups), 5:2 birds generally showed more interest in a novel object in the home pen which indicated increased risk taking and reduced fear while fasting. The 5:2 birds in this study showed no signs of learning the feeding schedule, and this unpredictability may also increase stress. Taken together, the effects of 5:2 vs. daily feed restriction on the welfare of broiler breeder pullets remain inconclusive and differ between feeding and fasting days. In addition to reducing stress by minimizing the number of fasting days, we suggest that a shift to more predictable schedules may help improve the welfare of broiler breeder pullets.

Growth heterogeneity in broiler breeder pullets is settled before the onset of feed restriction but is not predicted by size at hatch.

Uniform growth is a desirable trait in all large-scale animal production systems because it simplifies animal management and increases profitability. In parental broiler flocks, so-called broiler breeders, low growth uniformity is largely attributed to the feed competition that arises from quantitatively restricted feeding. As feed restriction is crucial to maintaining healthy and fertile breeders, several practices for reducing feed competition and the associated growth heterogeneity have been suggested and range from nutrient dilution by increasing fiber content in feed to intermittent fasting with increased portion size ("skip a day"), but no practice appears to be entirely effective. The fact that a large part of the heterogeneity remains even when feed competition is minimized suggests that some growth variation is caused by other factors. We investigated whether this variation arises during embryonic development (as measured by size at hatch) or during posthatch development by following the growth and body composition of birds of varying hatch sizes. Our results support the posthatch alternative, with animals that later grow to be small or large (here defined as >1 SD lighter or heavier than mean BW of the flock) being significantly different in size as early as 1 d after gaining access to feed ( < 0.05). We then investigated 2 possible causes for different postnatal growth: that high growth performance is linked 1) to interindividual variations in metabolism (as measured by cloacal temperature and verified by respirometry) or 2) to higher levels of social motivation (as measured in a social reinstatement T-maze), which should reduce the stress of being reared in large-scale commercial flocks. Neither of these follow-up hypotheses could account for the observed heterogeneity in growth. We suggest that the basis of growth heterogeneity in broiler breeder pullets may already be determined at the time of hatch in the form of qualitatively different maternal investments or immediately thereafter as an indirect result of differences in incubation conditions, hatching time, and resulting fasting time. Although this potential difference in maternal investment is not seen in body mass, tarsometatarsal length, or full body length of day-old chicks arriving at the farm, it may influence the development of differential feed and water intake during the first day of feeding, which in turn has direct effects on growth heterogeneity.

National HIV surveillance in South Africa--1993-1995.

OBJECTIVE: To determine the point prevalence of HIV infection by serological examination which, performed consistently over several years, serves to monitor the distribution and trend of the HIV epidemic in South Africa. DESIGN: Annual cross-sectional surveys conducted nationally, in October/November. SETTING: South Africa, including areas that used to be known as self-governing and independent national states. SUBJECTS: Pregnant women in the age group 15-49 years who attend antenatal clinic services provided by the public health services. OUTCOME MEASURES: HIV positivity as determined serologically. RESULTS: The rising trend found previously continues: HIV positivity in South Africa was found to be 4.25% in 1993, 7.57% in 1994 and 10.44% in 1995. In 1995 the highest rate was recorded in KwaZulu-Natal (18.23%) and the lowest in the Western Cape (1.66%). On the basis of certain assumptions it is estimated that these rates are indicative of 1.7 million sexually active adults having been infected with HIV by October/November 1995, plus a cumulative total of 40,000 infants. Women in their 20s had the highest age-specific prevalence rates, viz. 13.12% (20-24 years) and 11.03% (25-29 years). HIV positivity in pregnant teenagers was 9.5%. CONCLUSIONS: The HIV epidemic is firmly established in South Africa with a wide variation in provincial prevalence rates. Of particular public health significance is the finding of a high and rising prevalence rate in pregnant teenagers. The observed prevalence rate for 1995 is lower than expected, giving rise to guarded hope that provinces with the highest recorded rates are moving away from the exponential growth found hitherto.

The South African HIV epidemic, reflected by nine provincial epidemics, 1990-1996.

OBJECTIVES: To determine by serological examination the annual point prevalence rates of infection with the human immunodeficiency virus (HIV) in representative samples of subjects in the nine provinces of South Africa, 1990-1996. DESIGN: Annual cross-sectional point prevalence surveys conducted in October/November of each year. SETTING: South Africa, including areas that used to be known as self-governing and independent National States. SUBJECTS: Pregnant women in the age group 15-49 years who attend antenatal clinic services provided by the public health services, and who act as an indicator group of the HIV epidemic among the heterosexually active population. OUTCOME MEASURES: HIV positivity as determined serologically; done consistently over several years, this serves to monitor the distribution and trend of the HIV epidemic in each of the nine provinces of South Africa. RESULTS: Empirical data gained from seven annual, consecutive countrywide surveys demonstrate a wide geographical variation in the point prevalence rates of HIV infection. In October/November 1996 the point prevalence rates (%) were as follows: Western Cape 3.09, Northern Cape 6.57, Northern Province 7.96, Eastern Cape 8.10, Gauteng 15.49, Mpumalanga 15.77, Free State 17.49, KwaZulu-Natal 19.90 and North West 25.13. The weighted national average was 14.17%. There are indications that some of the provinces (KwaZulu-Natal and possibly Mpumalanga) might have passed a point of inflection suggesting deceleration in their specific rates of increase. These results are, however, counterbalanced by the exponential growth still being experienced in provinces with large populations such as Gauteng and the Eastern Cape. It is concluded that the net effect of these divergent trends currently affects the national figure only marginally. A major deflection from the exponential growth patterns seen hitherto can be anticipated only once all or most of the highly populated provinces have traversed their respective points of inflection. The exponential model significantly explains the HIV epidemics in the provinces. The combination of these provincial epidemics describes the initial exponential phase of the epidemic.

A population-based seroprevalence study in South Africa as a tool in the polio eradication initiative.

A seroprevalence study for poliomyelitis was carried out on a sample of sera from a serum bank used for a vitamin A study. Vaccination coverage was satisfactory (80% or more) in five of nine provinces, although a prevalence of antibody to polio of 80% or more was found in all provinces. Serologic immunity (i.e., the prevalence of neutralizing antibodies) exceeded vaccination coverage, suggesting secondary spread of vaccine virus. However, whether or not water was supplied through a piped system was not associated with secondary spread of vaccine virus to nonvaccinated children. Seroprevalence studies are a valuable adjunct to acute flaccid paralysis surveillance, which is the standard surveillance instrument for the poliomyelitis eradication initiative. The use of available and suitable serum banks for seroprevalence investigations is a relatively cheap monitoring option that can yield very valuable information for the eradication initiative.

National HIV surveillance--South Africa, 1990-1992.

The findings of three annual surveys of women attending antenatal clinics (at the end of 1990, 1991 and 1992) are presented here. These surveys form part of the National HIV Surveillance Programme. This programme is probably the most useful means of monitoring the trend and distribution of the epidemic. In all strata, a consistent rise in the HIV prevalence rate was found; it doubled almost every 12 months. The point prevalence rate in antenatal clinic attenders in South Africa increased from 0.76% in 1990 to 1.49% in 1991 and 2.69% in 1992. The prevalence rate was found to vary widely geographically: Natal/KwaZulu formed the spearhead of the epidemic with a 4.77% rate of HIV infection in 1992. Venda and the Cape appeared to be the least affected with rates of 0.64% and 0.66% respectively.

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 2. Immunity aspects.

An extensive poliomyelitis outbreak due to type 1 poliovirus took place in Natal/KwaZulu, South Africa, in 1987-1988, causing 412 paralytic cases. This epidemic differed from a previously described outbreak in Gazankulu, South Africa, in 1982 in that it occurred against a background of relatively good immunity. Thus, only 12% of patients lacked antibodies to types 2 and 3, indicating lack of previous immunization, and 76% of healthy children sampled in the epidemic area had serological immunity to all 3 types of poliovirus. The occurrence of extensive outbreaks in relatively well-immunized communities emphasizes the need to maximize herd immunity and reduce reservoirs of infection in the gut and in the environment, which can be achieved only with oral polio vaccine.

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 1. Epidemiology.

An epidemic of type 1 poliomyelitis occurred in Natal/KwaZulu in the eastern part of South Africa between December 1987 and November 1988. 412 poliomyelitis cases were reported, of whom 74% were younger than 5 years. The case-fatality rate was 8%. It is suggested that massive floods, experienced in the area 2 months earlier, triggered the outbreak.

Maternal glycosylated haemoglobin values after delivery of large infants and unexplained stillbirths.

Glycosylated haemoglobin (Hb A1) values were estimated immediately after delivery in 29 patients who had given birth to a large infant, in 25 who had delivered a macerated stillborn infant, and in 31 controls matched for age and parity. No difference in mean Hb A1 values was found between mothers of normal-sized and of large infants. The mean Hb A1 level for the mothers who had delivered a macerated stillborn infant was higher than that for the control group (8,26% v. 7,65%). Although this was not statistically significant, there were 5 patients with a raised Hb A1 value and a normal glucose tolerance test result; this may suggest gestational diabetes.

Breast-feeding - evaluation of a health education programme.

A health education programme which had the objective of increasing the practice of breast-feeding is evaluated. Women provided with health education are shown to have greater knowledge of the advantages of breast-feeding but unchanged behaviour as regards breast-feeding practice. A plea is made for a nation-wide effort to promote breast-feeding.

Carbohydrate metabolism in twin pregnancy.

Carbohydrate metabolism was evaluated in 26 women with a twin pregnancy and 26 women with a singleton pregnancy. The groups were similar in respect of age, parity and gestational age. Each woman had an oral glucose tolerance test. No significant differences in venous blood sugar values or insulin responses were found between singleton and twin pregnancies.

Trichomonas infection in pregnancy--does it affect perinatal outcome?

Antenatal patients free of Trichomonas vaginalis vaginal infection were compared with infected patients, half of whom were treated and half left untreated. The treated group was given benzoylmetronidazole 50 ml (2 g metronidazole equivalent) as a single dose. The mode of treatment was found to be very palatable and highly effective. The birth weights and gestational age at delivery were similar in all three groups.

Serological diagnosis of syphilis in pregnancy. Experiences at King Edward VIII Hospital, Durban.

Three different serological screening tests for syphilis were performed at the 'booking' visit of 500 antenatal patients at the King Edward VIII Hospital, Durban. The prevalence of active syphilis was 7,4%. The rapid plasma reagent test not only had a high biological false-positive rate at 11,8%, but also failed to detect 18,9% of the 37 patients diagnosed as having syphilis by means of the IgM-specific fluorescent treponemal antibody absorption (FTA-ABS) test. The Treponema pallidum haemagglutination (TPHA) test had a similarly high biological false-positive rate of 15,8%, but did not miss any of the 37 cases of active syphilis. The TPHA test is therefore advocated for screening patients for syphilis.