Full-fat insect meal in pelleted diets for weaned piglets: Effects on growth performance, nutrient digestibility, gastrointestinal function, and microbiota

Insects, such as the black soldier fly larvae (BSFL), are suggested as a sustainable novel protein source for pigs. The BSFL contains chitin, medium-chain fatty acids, and antimicrobial peptides, which could improve the gastrointestinal function and health of the post-weaning pig. The objective of this study was to investigate the effect of increased inclusion of full-fat BSFL in diets for post-weaning pigs on growth performance parameters, digestibility of nutrients, gut morphology, and the microbial community in the colon. Eighty crossbred pigs were weaned at approximately 32 days of age, with an average weaning weight of 10.6 ± 0.8 kg. For four weeks, pigs were fed: a control diet or one of three diets containing increasing amount of full-fat BSFL meal at 4.76%, 9.52%, and 19.06%. The average daily gain (ADG) for the overall experimental period showed a negative cubic effect of dietary treatment, where the ADG was highest for pigs fed the control diet and lowest for pigs fed the diet with 4.76% BSFL (P = 0.031). Increased level of full-fat BSFL in the diet did not affect feed efficiency or fecal consistency. A linear reduction in the coefficient of apparent total tract digestibility (CATTD) of crude protein (P = 0.011) was found for increasing inclusion of BSFL, whereas for crude fat both the coefficient of apparent ileal digestibility (P = 0.043) and the CATTD (P < 0.001) increased linearly. Jejunal, ileal, or colonic morphometry was not affected by the BSFL inclusion. No differences in the short-chain fatty acid concentrations were detected among the dietary treatments, but a few minor changes in the colon microbiota were observed. At the phylum level, the colon microbiota was dominated by Bacteroidota and Firmicutes, but there was no clear pattern relationship with the BSFL inclusion level. At the genus level, the inclusion of BSFL in the diet reduced the relative abundance of Lactobacillus (P = 0.015) compared to the control. Collectively, the results indicate that up to 19.06% of full-fat BSFL meal could be included in a balanced diet for post-weaning pigs with only minor effects on growth performance, general gut function, and gut health.acceptedVersio

Gene expression and gastrointestinal function is altered in piglet small intestine by weaning and inclusion of Cyberlindnera jadinii yeast as a protein source

This study investigated the effect of feeding Cyberlindnera jadinii yeast on the development of gastrointestinal function and health in piglets during the first two challenging weeks after weaning. Changes in gastrointestinal function were mainly attributed to weaning, and not to dietary treatment. The post-weaning (PW) transcriptome profiles differed between dietary treatments showing an overall higher number of differentially expressed genes (DEGs) in control piglets than in yeast-fed piglets. DEGs in jejunum and ileum were compared between sampling timepoints within each feeding group and divided into clusters with similar expression trends. Pathway enrichment analysis was run on each cluster to reveal PW physiological changes. Weaning induced downregulation of several immune functions in the control piglets, which was not as evident in the yeast fed piglets. The results indicate that feeding C. jadinii yeast can improve PW gut homeostasis and give more robust piglets.publishedVersio

Longitudinal analysis of the faecal microbiome in pigs fed Cyberlindnera jadinii yeast as a protein source during the weanling period followed by a rapeseed‑ and faba bean‑based grower‑finisher diet

publishedVersio

Feed intake, nutrient digestibility, growth performance and general health of piglets fed increasing levels of yeast

In Norway, the climatic conditions and limited agricultural area impedes production of protein-rich plant-feedstuff, leading to the current dependency of import of soybeans. Norway has large forest areas, which constitute a huge lignocellulosic biomass with unused potential as resources for production of microbial feed ingredients with high-protein content such as yeast. Studies have also shown that yeast or other bioactive compounds may help the piglets to better cope with challenges due to weaning and transition of feed, by providing beneficial effects on the intestinal health. The aim of this thesis was to evaluate the effect of increasing dietary level of Candida utilis yeast biomass on nutritional value and general health responses in early weaned piglets over a period of four weeks post-weaning. A total of 48 piglets, weaned at four-weeks of age, were distributed to four dietary treatments; a control feed (0 % yeast) and three diets containing increasing amounts of yeast corresponding to 10 % (Yeast 10), 20 % (Yeast 20) and 40 % (Yeast 40) of total CP in the diet. Body weight gain and feed intake were registered weekly. From day 18 to 28, the piglets received feed labeled with Y2O3 as digestibility marker. Feces were collected in a period of five days for determination of apparent total tract digestibility (ATTD) of nutrients, and ileal content were collected at the termination day for determination of apparent ileal digestibility (AID) of nutrients. The first week PW there was a linear increase in average daily gain (ADG) and fecal DM by increasing levels of yeast, indicating the yeast may improve intestinal health of weanling piglets. In addition, for the four-week period, average fecal consistency scores were significantly lower piglets fed Yeast 40 compared to the control. Digestibility of most nutrients and feed utilization of the diets containing yeast was similar to the control, except for the Yeast 20 diet. Digestibility results showed an improved ATTD of ash in the piglets fed Yeast 10 and Yeast 40. In conclusion, the results of this study indicate that Candida utilis yeast produced from lignocellulosic biomass may be a suitable protein source in feed for weanling piglets.Klimatiske forhold og begrensede områder med dyrkbart areal, vanskeliggjør produksjonen av proteinrike plantefôrråvarer i Norge. Dette gjør at vi i dag er avhengige av import av soyabønner som proteiningrediens i kraftfôr. Norge har imidlertid store skogområder, som med ny teknologi kan utnyttes til produksjon av proteinrike mikroorganismer, slik som gjær. Det er også vist at gjær eller bruk av lignende bioaktive komponenter i fôret kan ha positiv innvirkning på tarmhelsen hos grisunger under avvenning. Hensikten med denne oppgaven var å evaluere næringsverdi og helserespons hos tidlig avvente smågris, ved økende nivåer av gjæren Candida utilis i fôret, i de første fire ukene etter avvenning. 48 griser avvent ved fire ukers alder ble fordelt på fire ulike dietter; et kontrollfôr (0 % gjær) og tre dietter med økende innhold av gjær tilsvarende 10 % (Yeast 10), 20 % (Yeast 20) og 40 % (Yeast 40) av totalt råproteininnhold i diettene. Fôrinntak og vekt ble registret ukentlig, og fra dag 18 til 28 i forsøksperioden var fôret tilsatt markør (Y2O3) for bestemmelse av fordøyelighet. Det ble samlet gjødsel over en periode på fem dager for bestemmelse av apparent totalfordøyelighet (ATTD) av næringsstoffer, og tarminnhold fra ileum ble samlet avslutningsvis for bestemmelse av apparent ileal fordøyelighet (AID) av næringsstoffer. Den første uken etter avvenning var det en lineær økning i gjennomsnittlig daglig vekst (ADG) og tørrstoff i gjødsel, ved økende innhold av gjær i fôret. Dette indikerer at gjæren kan bedre tarmhelsen under avvenning. Gjennomsnittlig gjødselscore for forsøksperioden var signifikant lavere hos dyrene som fikk Yeast 40 dietten sammenlignet med de som fikk kontrollfôret. Fordøyeligheten av de fleste næringsstoffene og fôrutnyttelse av diettene som inneholdt gjær var sammenlignbart som for kontrolldietten, bortsett fra for Yeast 20 dietten. Fordøyelighetsresultatene viste forbedret ATTD av aske hos griser som fikk Yeast 10 og Yeast 40 diettene. Som konklusjon viser resultatene i forsøket at Candida utilis gjær fremstilt fra lignocellulosisk biomasse kan være en egnet proteinkilde i fôr til avvente smågris

Nye proteinkilder til avvente smågris – effekt på vekst, tarmfunksjon og helse

The world is facing a growing food demand from an ever-increasing population. To meet this challenge, new resources must be utilized through innovative solutions. Meat is a valuable protein source in the human diet. However, in Norway, a northern country with limited agricultural land, we are today dependent on imports of protein-rich ingredients to feed our livestock. To increase self-sufficiency and ensure future food security, there is a need for alternative protein sources that do not occupy land areas suitable for human food production. The Cyberlindnera jadinii yeast and black soldier fly larvae (BSFL) are two promising novel feed ingredients that can be produced from renewable resources or side-streams, and thereby contribute to a circular bioeconomy. These two novel feed ingredients also contain several bioactive compounds which might be beneficial for the gastrointestinal function and health of the weaned piglet. It is well known that weaning causes changes in the gastrointestinal structure and function, and compromises health. The aim of this thesis was to evaluate C. jadinii yeast and BSFL as novel protein sources for weanling piglets and investigate if these ingredients could improve post-weaning (PW) challenges. Two experiments were conducted. Experiment I (Paper I and II) investigated the effect of a high dietary inclusion of C. jadinii yeast (14.6%) on the early PW physiological changes in piglets. Results showed early PW changes in gastrointestinal function and health parameters, but changes were mainly time-dependent, not diet-dependent. However, the inclusion of C. jadinii yeast improved the apparent ileal digestibility of crude protein and affected the PW small intestinal gene expression. Weaning induced downregulation of several immune functions in the small intestine of the control piglets, whereas this downregulation was not as evident in the yeast-fed piglets. Collective, the gastrointestinal function, transcriptional, and plasma immunological results indicated a less evident acute weaning phase in piglets fed yeast. In Experiment II (Paper III), the effect of increasing inclusion of full-fat BSFL meal (< 19.1%) on growth performance and gastrointestinal function in piglets was investigated for a four-week period PW. High inclusion of full-fat BSFL meal did not compromise growth performance, but the apparent total tract digestibility of crude protein was reduced by increased inclusion of BSFL, whereas both the apparent ileal and total tract digestibility of crude fat was improved. The inclusion of BSFL also affected the colon microbiome by lowering the relative abundance of Lactobacillus, although no effect was seen on microbial diversity indices. The discussion of this thesis focused on comparing the two investigated feed ingredients. In conclusion, both C. jadinii yeast and BSFL meal are high-value protein sources and suitable feed ingredients for PW piglets, but future studies should investigate methods to improve the protein digestibility of the BSFL. Neither of the novel ingredients adversely affected the gastrointestinal function and health of the piglets. In conclusion, both C. jadinii yeast and BSFL could improve gut homeostasis PW, but especially C. jadinii yeast showed potential to improve PW gastrointestinal challenges, giving more robust piglets.Med en stadig økende verdensbefolkning, øker også behovet for mat. For å møte denne utfordringen må vi utnytte nye ressurser på innovative måter. Kjøtt er en verdifull proteinkilde i kostholdet, men i Norge er vi i dag avhengige av å importere proteinrike ingredienser for å fôre husdyrene våre. For å øke selvforsyning og sørge for framtidig matsikkerhet, er det behov for alternative proteinkilder som ikke opptar landarealer egnet til produksjon av menneskemat. Gjæren Cyberlindnera jadinii og larver av svarte soldatfluer (black soldier fly larvae - BSFL) er to alternative proteinkilder som kan produseres fra fornybare ressurser eller sidestrømmer, og dermed bidra til sirkulær bioøkonomi. Disse to fôringrediensene inneholder også bioaktive komponenter som kan være gunstige for smågrisens tarmfunksjon og helse etter avvenning. Det er kjent at avvenning forårsaker endringer i tarmstruktur og -funksjon, og dermed påvirker smågrisens helse negativt. Hensikten med denne avhandlingen var å evaluere C. jadinii og BSFL som to alternative proteinkilder i fôret til smågris etter avvenning, og undersøke om disse ingrediensene kan minske utfordringene som oppstår ved avvenning. To forsøk ble gjennomført. Det første forsøket (Artikkel I og II) undersøkte effekten av et fôr med høy andel C. jadinii gjær på fysiologiske endringer hos smågris, kort tid etter avvenning. Resultatene viste endringer i tarmfunksjon og helse i perioden etter avvenning, men endringene var først og fremst tidsavhengige og ikke fôravhengige. Tilsetning av C. jadinii gjær i fôret økte imidlertid ilealfordøyelighet av råprotein, og påvirket genuttrykket i tynntarmen etter avvenning. Gener involvert i flere immunologiske funksjoner ble nedregulert etter avvenning, men dette var ikke like tydelig hos smågrisene som hadde spist gjær. Samlet sett antydet resultatene for tarmfunksjon-, genuttrykk- og blod immunologiske analyser at smågrisene som spiste gjær hadde mindre tydelig akuttfase etter avvenning. Det andre forsøket (Artikkel III) undersøkte effekten av økende tilsetning av fullfett BSFL-mel (< 19.1%) på vekstparametere og fordøyelsesfunksjon hos smågris, i en fire ukers periode etter avvenning. Høy tilsetning av BSFL hadde ikke betydelig effekt på vekstparametere, men reduserte fekalfordøyelighet av råprotein. Både ileal- og fekalfordøyelighet av råfett økte imidlertid ved økt tilsetning. Mikrobiomet i tykktarmen ble også påvirket. Tilsetning av BSFL reduserte den relative mengden av Lactobacillus i tykktarmen, men påvirket ikke det mikrobielle mangfoldet. Diskusjonen i denne avhandlingen fokuserte på sammenligning av de to undersøkte fôringrediensene. Avhandlingen konkluderer med at både C. jadinii gjær og BSFL-mel er høyverdige proteinkilder og egnede fôringredienser for smågris etter avvenning, men fremtidige studier bør undersøke metoder for å forbedre proteinfordøyeligheten av BSFL. Ingen av de undersøkte ingrediensene hadde negativ innvirkning på tarmfunksjonen eller helsen til smågrisene. Både C. jadinii gjær og BSFL kan bidra til å forbedre tarmhomeostasen etter avvenning, men spesielt C. jadinii har potensial til å forbedre avvenningsutfordringer og gi mer robuste smågriser

Candida utilis yeast as a protein source for weaned piglets: Effects on growth performance and digestive function

Yeast such as inactivated Candida utilis produced from lignocellulosic biomass from underutilized wood co-products as a second-generation sugar source is a potentially sustainable protein feed ingredient in diets for piglets. This study aimed to evaluate the effects of C. utilis added to diets for weaned piglets on growth performance and digestive function when replacing main protein sources. Forty-eight piglets weaned at 30 days of age, with a mean starting weight of 11.06 ± 0.84 kg were fed one of four dietary treatments for 28 days: a conventional control diet with soybean meal, fishmeal, rapeseed meal, and potato protein or one of three experimental diets containing 10, 20 or 40% crude protein (CP) from yeast (CU10, CU20, and CU40, respectively). Adding yeast to diets did not affect growth performance compared with the control. The diet with 40% CP from C. utilis had higher apparent total tract digestibility (ATTD) of CP compared with the control (P = 0.034) and higher ATTD of ash (P < 0.001) compared with the control. The ATTD of neutral detergent fiber decreased in the CU40 diet compared with the control (P = 0.006). The apparent ileal digestibility (AID) of ash increased (P = 0.001) in the CU40 diet compared with the control, while the AID of CP and amino acids was unaffected. Villi-height increased in jejunum (P = 0.007) and ileum (P = 0.047), and villus-height: crypt-depth ratio increased (P = 0.001) in jejunum of piglets fed the CU40 diet compared with the control. Fecal dry matter increased linearly with increasing levels of C. utilis in the diets at day 7 after weaning (P = 0.001) and was higher for the CU40 group compared with the control group at day 21 after weaning (P = 0.027). Trypsin activity and messenger RNA expression of nine genes encoding for nutrient transporters in the jejunum did not differ among diets. Collectively, the results indicated that C. utilis can replace 40% of CP from the main protein sources traditionally used in diets for weaned piglets while maintaining growth and improving digestive function.acceptedVersio

Replacing soybean meal with rapeseed meal and faba beans in a growing-finishing pig diet: Effect on growth performance, meat quality and metabolite changes

Rapeseed meal and faba beans (RSM/FB) can serve as an alternative to imported soybean meal 35 (SBM). In this study, forty Norwegian crossbred ([Landrace x Yorkshire] x Duroc) growing36 finishing pigs (108.7±4.2 kg final BW) were fed a diet with either SBM or RSM/FB as protein 37 sources. RSM/FB increased feed conversion ratio (P=0.04) in the finishing period, reduced 38 lightness (P=0.04) and yellowness (P=0.004) of meat, changed amounts of individual fatty acids, 39 but not of total SFA, MUFA and PUFA. Importantly, RSM/FB reduced the glucose level (P < 40 0.05) in meat. Lower pyroglutamic acid (P = 0.06) in RSM/FB indicate lower oxidative stress in 41 pre-rigor muscle cell. Increased abundance of free amino acids, sweet tasting metabolites, reduced 42 warmed-over flavor and flavor attributes indicated desirable properties of RSM/FB meat. To 43 conclude, RSM/FB in pig diet supported a high growth performance and carcass quality 44 comparable to SBM and had a positive effect on meat quality.acceptedVersio

Gene expression and gastrointestinal function is altered in piglet small intestine by weaning and inclusion of Cyberlindnera jadinii yeast as a protein source

This study investigated the effect of feeding Cyberlindnera jadinii yeast on the development of gastrointestinal function and health in piglets during the first two challenging weeks after weaning. Changes in gastrointestinal function were mainly attributed to weaning, and not to dietary treatment. The post-weaning (PW) transcriptome profiles differed between dietary treatments showing an overall higher number of differentially expressed genes (DEGs) in control piglets than in yeast-fed piglets. DEGs in jejunum and ileum were compared between sampling timepoints within each feeding group and divided into clusters with similar expression trends. Pathway enrichment analysis was run on each cluster to reveal PW physiological changes. Weaning induced downregulation of several immune functions in the control piglets, which was not as evident in the yeast fed piglets. The results indicate that feeding C. jadinii yeast can improve PW gut homeostasis and give more robust piglets

Candida utilis yeast as a protein source for weaned piglets: Effects on growth performance and digestive function

Yeast such as inactivated Candida utilis produced from lignocellulosic biomass from underutilized wood co-products as a second-generation sugar source is a potentially sustainable protein feed ingredient in diets for piglets. This study aimed to evaluate the effects of C. utilis added to diets for weaned piglets on growth performance and digestive function when replacing main protein sources. Forty-eight piglets weaned at 30 days of age, with a mean starting weight of 11.06 ± 0.84 kg were fed one of four dietary treatments for 28 days: a conventional control diet with soybean meal, fishmeal, rapeseed meal, and potato protein or one of three experimental diets containing 10, 20 or 40% crude protein (CP) from yeast (CU10, CU20, and CU40, respectively). Adding yeast to diets did not affect growth performance compared with the control. The diet with 40% CP from C. utilis had higher apparent total tract digestibility (ATTD) of CP compared with the control (P = 0.034) and higher ATTD of ash (P < 0.001) compared with the control. The ATTD of neutral detergent fiber decreased in the CU40 diet compared with the control (P = 0.006). The apparent ileal digestibility (AID) of ash increased (P = 0.001) in the CU40 diet compared with the control, while the AID of CP and amino acids was unaffected. Villi-height increased in jejunum (P = 0.007) and ileum (P = 0.047), and villus-height: crypt-depth ratio increased (P = 0.001) in jejunum of piglets fed the CU40 diet compared with the control. Fecal dry matter increased linearly with increasing levels of C. utilis in the diets at day 7 after weaning (P = 0.001) and was higher for the CU40 group compared with the control group at day 21 after weaning (P = 0.027). Trypsin activity and messenger RNA expression of nine genes encoding for nutrient transporters in the jejunum did not differ among diets. Collectively, the results indicated that C. utilis can replace 40% of CP from the main protein sources traditionally used in diets for weaned piglets while maintaining growth and improving digestive function